The Habitat of the Eurypterida/Chapter I

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From all over the world there have been recorded fourteen genera and between 150 and 160 species of eurypterids. Of these considerably more than half occur in the Siluric, about a third occurring in the Upper Siluric alone. No remains have been found in beds higher than the Permic, and until 1882 it was supposed that there were none below the Siluric. In that year Walcott discovered a few fragments in the Utica shale, of Upper Ordovicic age, and an even more remarkable fauna in the Pre-Cambric Belt Terrane of Montana. In 1901 Beecher discovered an almost perfect eurypterid in the Upper Cambric of Missouri. These discoveries, together with several more recent ones from the Ordovicic, show that the Eurypterida ranged from the Pre-Cambric through the Permic, reaching their acme in numbers, development and diversity of types in the Upper Siluric. In the following review of the occurrence North America alone will be considered first and then the rest of the world. Until the Monograph on the Eurypterida of New York appeared there was no one book containing all the information about the North American species, and it was necessary for one in quest of such knowledge to search laboriously through state reports and numerous periodicals. Now all the data have been systematically brought together and greatly added to, so that it will be unnecessary to dwell at great length upon the American formations. For the rest of the world, unfortunately, there is no one book to which the student may be referred, so that one is compelled to consult the literature of each country in each continent thus gradually bringing together the work that has been done. Because the foreign periodicals and books now out of print are inaccessible to many, a more detailed account will be given of the distribution, and the nature and correlation of the formations in other countries than is required for America.

Pre-Cambric. The earliest representative of the eurypterids is Beltina danai discovered by Walcott in the Greyson shales in the ​middle part of the Belt Terrane in Montana. The remains are very numerous, most of them being exceedingly thin films flattened in a calcareous shale and showing no definite surface markings (288, 21). Weller has collected specimens from the Altyn limestone at the type locality north of Altyn in the valley of Swift Current Creek, Montana, at the base of the Appekunny Mountains where the remains are embedded in a fine calcarenyte matrix and show surface markings (288, 40, pl. 7, fig. 4). Specimens have also been collected from the Altyn limestone at about the same horizon near Johnson Creek on The Continental Divide, Alberta, Canada. These show surface markings, and have been referred by Walcott to B. danai (288, 40, pl. 7, figs. 2, 2a, 3).

In a recent communication from Dr. Walcott, I have his statement about the occurrence of the merostome remains in the different sections. In the southeastern area of the Big Belt Mountains he found a series of sandy shales and sandstones between the top of the Newland limestone and the base of the Greyson; these carried Beltina. In the sections in the Little Belt Mountains Walcott found it difficult to determine whether the shales carrying Beltina belonged to the Greyson or to the Newland. In the Northern Montana section the merostome remains are found in the lower portion of the Altyn limestone, so that, concludes Walcott, "the correlation on the basis of fossil evidence is that the Greyson and Altyn are about the same age."^[1] The fossils from the Altyn limestone were identified by Walcott as Beltina danai, and Clarke and Ruedemann agree that the fragments are remains of merostomes. They are, however, skeptical about the correlation of the Altyn with the Belt terrane and they are justified in this skepticism so long as the correlation is based upon the fossils alone, for if the organic remains in the Belt terrane are not eurypterids and are not the same as those in the Altyn, then the correlation is unfounded. Furthermore, the palaeontological evidence alone would not be sufficient for correlation, and, if, as I believe, these Pre-Cambric formations are to be regarded as of continental origin, then neither physical nor faunal data will lead to correlations, since the same lithological successions will be repeated time and again in different localities and in addition the synchroneity of river faunas is difficult to establish.

Thus at present it is impossible to say which authority is to be accepted. Walcott plans to do more work on these sections in the ​course of which he may find better preserved fragments in the Belt terrane, leaving no doubt as to the nature of the organisms; or, he may find other structural and stratigraphic evidence for the correlation. "On the basis of lithologic characteristics," he says, "the Altyn would be correlated with the Newland limestone, and the Grinnell and Appekunny with the arenaceous series above the Newland limestone." But he further points out that "In deposits of the character of those of the Algonkian in Montana, lithologic characteristics are really of very little value over extended areas, as most of the calcareous formations are in the form of great lentils, and these are not comparable with the calcareous deposits of the Palaeozoic."

Cambric. In the Middle Cambric there are undoubted marine Merostomata, discovered by Walcott in 1910 in the Stephen formation in British Columbia, Canada. He has described two genera, Sidneyia and Amiella, referring them to the Eurypterida in the sub-order Limulava. As will be shown later, these forms are not true eurypterids, and need, therefore, no further mention here.

The only unquestionable eurypterid from the Cambric is Beecher's Strabops thacheri from the Potosi limestone at Flat River, St. François county, Missouri (19, pl. VII). Of this species a single specimen was found for which the genus was erected. It is a nearly complete individual, the dorsal aspect of which is well shown, though none of the appendages are visible. It occurs in a yellowish, argillaceous calcilutyte from one of the lower members of the Potosi. The slab upon which Strabops occurs contains no other organic remains,^[2] but Beecher has described a collection made by Nason from these same beds in which there is an abundant marine fauna consisting of fragments of trilobites with a few brachipods and other forms (Hyolithes and a small Platyceras) (20, 362, 363). It is to be regretted that Beecher did not, or was not able to specify more exactly the stratum in which he found the eurypterid, for the Potosi limestone in the Flat River section is 350 feet thick, not counting the 106 feet of slates and conglomerate below and another 100 above, all of Potosi age, and of course, it is by no means certain that the marine fossils occurred in the same bed with the eurypterid. In fact, so far as the material is concerned, this seems not to have been the case.

Ordovicic. From the Ordovicic until just recently only one occurrence had been noted, that of Echinognathus clevelandi Walcott, ​described from the Utica shale of Holland Patent, New York (281), where one cephalic appendage and a portion of a thoracic somite were found. On the same piece of slate with these fragments Walcott found two characteristic Utica fossils, Leptobolus insignis and Triarthrus becki, and from the same locality comes a large graptolite fauna including Dendrograptus tenuiramosus, Climacograptus bicornis, as well as Schizocrania filosa and Endoceras proteiforme.

Lately there have been some extremely interesting discoveries of eurypterids in the Normanskill and Schenectady shales and sandstones (Black River and early Trenton age, respectively) of the Mohawk and Hudson valleys. Professor G. H. Chadwick has very recently found eurypterid remains in the sandstones of the Broom Street Quarry at Catskill, New York, in the Normanskill beds which until then had yielded only a graptolite fauna. Clarke and Ruedemann have described the species and also the beds from which they come. The eurypterids are very abundant in the sandstones though poorly preserved, but in the intercalated black shales, while less numerous they show better preservation. They are associated with graptolites and plant remains. Six species have been described by Clarke and Ruedemann. Eurypterus chadwicki, Eusarcus linguatus, Dolichopterus breviceps, Stylonurus modestus, Pterygotus ? (Eusarcus) nasutus, P. normanskillensis. Entire individuals are absent, the fauna being made up chiefly of carapaces.

The first profuse Upper Ordovicic fauna is found in the Schenectady shales (Trenton age), originally referred to the Frankfort. A preliminary notice of these specimens which appeared in 1910 (38, 31) shows that these remains "usually in fragmentary condition, abound most freely in fine-grained black shale, intercalated between thick calcareous sandstone beds. . . . . but they also occur in the sandy passage beds between the two. The sandy shales are full of organic remains, partly of the supposed seaweed Sphenothallus (Sphenophycus) latifolium Hall and partly of what appear to be large unidentified patches of eurypterid integument. In the black shales the eurypterid remains are rarer, but their surface sculpture is excellently retained, and here their organic associates are Climacograptus typicalis and Triarthrus becki. As a result of imperfect retention of these eurypterids in the rocks where they most abound and their sparseness in the shales which have best preserved them, we are still left in ignorance of the full composition of the assemblage, but it is safe to say genera, species and individuals were abundant at this early ​period and the evolution of distinctive characters . . . . had progressed to so sharp a differentiation that we are compelled to carry back farther in history, some of the commoner generic designations. These remains in the Frankfort [Schenectady] shale are distributed through fully 1500 feet of strata off a northeast-southwest coast line in an area of maximum deposition." Clarke and Ruedemann have described eleven species^[3] Eurypterus megalops, E. pristinus, E. ? (Dolichopterus ?) stellatus, Eusarcus triangulatus, E. ? longiceps, Dolichopterus frankfortensis, D. latifrons, Hughmilleria magna, Pterygotus nasutus, P. prolifica, Stylonurus ? limbatus.

A few fragments found as early as 1874 in the upper part of the Cincinnati group near Clarkesville, Clinton County, Ohio, were originally described by S. A. Miller (174) as Megalograptus welchi, under the mistaken supposition that they represented a graptolite, but were later determined by A. F. Foerste to be eurypterid remains. The specimens are much broken, representing two endognathites with one postabdominal segment. They occur in a blue marl three feet above a wave-marked layer of limestone, in the Liberty beds where they are associated with a typical marine fauna mainly of crinoids and some trilobites.

Siluric. Lower Siluric or Niagaran. In the Lower Siluric are several cases of the presence of eurypterid remains in marine formations. Hall's species of Eurypterus prominens from the Clinton greenish sandstone of Cayuga County, New York, was described from a single cephalon, and an unidentified species of Eurypterus is recorded from the Arisaig of Nova Scotia (39, 87). Whiteave's Eurypterus (Tylopterus) boylei from the Guelph dolomites of Ontario is a species founded upon a single somewhat crushed, but otherwise nearly complete individual. It is found in a porous, coarse-grained dolomite, and shows an unusually thickened exoskeleton, a thickening common in other members of the Guelph fauna and indicating, according to Clarke and Ruedemann, extremely saline conditions (39, 218).

Quite recently a new eurypterid horizon has been discovered by M. Y. Williams in the shales overlying the Lockport and underlying the Guelph of Ontario, Canada. Along the banks of the Eramosa River between Rockwood and Guelph the top of the Lockport formation is exposed, and is seen to consist of a series of "thin-bedded, dark ​grey or chocolate brown, bituminous dolomites which at some localities include bituminous shales," and to which Williams has given the name Eramosa beds (303, 1).

The bituminous nature of the dolomites and intercalated shales is indicative of near-shore conditions, and since these succeed the more purely marine facies of the typical Lockport, a shoaling or withdrawal of the sea, with a greater dominance of terrestrial sedimentation, is implied. The fauna is confined within some six inches of the bituminous shales and though fragments of a dozen or more species, including one eurypterid, have been found in abundance, not even generic identifications could be made with certainty. Williams gives the following list (303, 3):

Eusarcus logani Williams

Monomorella cf. orbicularis Billings

Orthis ? near tenuidens Hall

Spirifer radiatus Sowerby ?

Anoplotheca ? sp.

Lichenalia concentrica Hall

Orbiculoidea subplana (Hall)

Camarotoechia whitei (Hall)?

Whitfieldella nitida Hall?

Meristina ? sp.

Conularia niagarensis Hall?

Conularia sp.

The Lower Siluric occurrences, thus, are in formations containing undoubted and abundant marine faunas, but the eurypterids are represented either by fragments, or, in the case of the Guelph specimen, by a single though nearly perfect individual.

A recent discovery of considerable interest is the finding by Professor Van Ingen of Princeton University, of eurypterid remans in what appears to be the Tuscarora and associated beds of Swatara Gap, Lebanon County, Pennsylvania (39, 418, 419). In beds carrying Arthrophycus harlani ? he found:

1. Eurypterus maria. Large and small carapaces.
2. Dolichopterus cf. otisius. Medium sized carapace.
3. Stylonurus myops. Large and small carapaces.
4. Hughmilleria shawangunk. Large carapace.
5. Pterygotus cf. globiceps. Small carapace.
6. Swimming leg of a Pterygotus or Hughmilleria.

Another bed labeled 182 B 23 has afforded a carapace not ​distinguishable from Eurypterus maria. A bed, said to occur between a horizon containing what is apparently a Clinton fauna (B 8x) and one containing a Rochester (or Lockport) fauna (B 19x) and numbered B 16 h, contained the following remains:

1. Small carapaces, belonging to species closely related to or identical with Eurypterus maria, Hughmilleria shawangunk and Pterygotus globiceps.
2. A patch of integument with finely preserved sculpture identical with that ascribed to Stylonurus sp.
3. Stylonurus myops. Fragmentary, medium sized carapace.
4. Coxa, probably belonging to Hughmilleria.
5. Small telson of an Erettopterus.

Middle Siluric or Salinan. In the Middle Siluric of North America are several interesting occurrences of eurypterids, and the first appearance of well preserved individuals in large numbers. Specifically indeterminable fragments of Hughmilleria and carapaces of Dolichopterus (cf. D. otisius) or Hughmilleria have been found along the Pennsylvania-Maryland border in a hard black shale which is "sandy at the top and pitted by rust-stained worm-tubes" (267, 5), and which is interbedded between two sandstone members of the Keefer sandstone member of the McKenzie formation at the base of the Salina.

Of far greater interest and importance, however, are the faunas of the Pittsford and Shawangunk shales of New York and Pennsylvania. At Pittsford, Monroe County, New York, five species (or varieties) of eurypterids have been found: Eurypterus pittsfordensis Sarle, Hughmilleria socialis Sarle, H. socialis var. robusta Sarle, Pterygotus monroensis Sarle and Stylonurus (Ctenopterus) multispinosus Clarke and Ruedemann. This fauna is represented by numerous individuals, many of them well preserved, and by many fragments, but typical marine fossils are absent from the shales, although crustacea such as Emmelezoe decora and Pseudoniscus roosevelti occur. The eurypterids are here preserved in a remarkable state of perfection, the fauna being found in two thin layers of the black shales (lower one 1 foot 2 inches thick, upper one 10 inches thick) (240, 1082) and the eurypterids are in such abundance that some layers are "literally packed" with the remains. The entire fauna from these beds as reported by Sarle (240, 1081) is: Phyllocarida, 2; Synxiphosura, 1; Eurypterida, 6.

In the associated dolomitic layers were found Graptolitida, 1; Annelida (denticles), 3; Brachiopoda, 1; Pelecypoda, 1; Cephalopoda, 2; Ostracoda, 1.

​A recent discovery by Professor Gilbert van Ingen has brought to light some eurypterid remains from a loose block found lying in Oriskany Creek, 3 miles south of Clinton, New York. Three carapaces and several other fragments were found, the block also being "full of lingulas and orbiculoideas" (39, 421). A new species, Eusarcus vaningeni Clarke and Ruedemann was made, to include these specimens which closely resemble E. cicerops of the Shawangunk of Otisville and may represent the adult of that species.

From the shale beds in the Shawangunk conglomerate at Otisville, Orange County, New York, a large fauna of eurypterids has been obtained, but other fossils except Ceratiocaris are absent. Here in the Shawangunk Mountains of Eastern New York is a great series 630 feet thick of the Shawangunk grit resting upon the Hudson River shales. The series consists of alternating shales varying from 2 to 6 inches in thickness, and conglomerates or sandstones from 1 to 50 feet thick, the shale bands containing the merostomes. Some of the specimens though only 2.5 mm. long "are perfectly preserved and are by far the youngest and smallest yet recorded. In regard to the occurrence Clarke says: "In the Shawangunk section we have a fauna constantly repeating itself through a thickness of 650 feet which elsewhere appears only and briefly at the base of the Salina" (36, 303). The perfect specimens are all of young individuals, adults being represented only by fragments. The species recorded are: 1. Eurypterus maria Clarke, 2. Eusarcus? cicerops Clarke, 3. Dolichopterus otisius Clarke, 4. D. stylonurus Clarke and Ruedemann, 5. Stylonurus (Ctenopterus) cestrotus Clarke, 6. S. (Ctenopterus) sp. α, β, γ, 7. S. myops Clarke, 8. S. sp., 9. Hughmilleria shawangunk Clarke, 10. Pterygotus globiceps Cl. and R.

From the middle part of the Shawangunk grit of Delaware Water Gap, Pennsylvania, intercalated black shales similar to those in New York have furnished eurypterids. These were discovered by Mr. Paul Billingsley of Columbia University, who collected a large amount of material and who reports that the fragments are all dissociated, the carapaces commonly occurring by themselves, and separated from the abdominal segments, as if arranged by violent currents. Professor G. van Ingen and Mr. J. C. Martin have also collected extensively from this section. From their large number of specimens Clarke and Ruedemann have been able to identify Nos. 1, 3, 7, 9, 10 of the list of species recorded from the Shawangunk of Otisville, and they make the comment that "Unfortunately, the maceration, ​already so prevalent in much of the eurypterid material at Otisville, has at the Delaware Water Gap reached such a destructive degree that the shale is filled with a mass of comminuted eurypterid fragments" (39, 417).

Upper Siluric or Monroan. The Bertie waterlime of New York of Upper Monroan age has long been famous for the wonderful eurypterid fauna which it contains. This has been found in two localities: (1) in the quarries in North Buffalo, Erie County, and (2) in Herkimer County; there are scattered occurrences of single species in other localities, which will be referred to below. The quarries at Buffalo have yielded the largest number of remains, the specimens having been sent in great numbers to museums all over the world, and the rock has now been so well worked over that probably no new disclosures will be made. For purposes of study of the entire fauna of the Bertie the large collection in the Museum of the Buffalo Society of Natural Sciences offers excellent opportunities. The Bertie contains the largest eurypterid fauna of any one formation in the world, there being recorded fourteen species (39, 89) referred to four genera: Eurypterus (5 sp.), Pterygotus (5 sp.), Eusarcus (1 sp.), and Dolichopterus (3 sp.). The specimens are for the most part astonishingly well preserved, but other organisms are extremely rare. In the Museum above referred to are a few specimens of marine organisms obtained from the formation which furnished the eurypterids. One slab of the waterlime about 1¼ inches thick shows on one side an Orthoceras undulatum which is very much worn, the siphuncle being exposed and the surface macerated (No. 13310 E 1639 of Buf. Soc. Nat. Sci. Coll.) and on the other side is a well preserved Eurypterus head (11461 E 976). There is one other specimen of O. undulatum (13309, E 1638) of a very carbonaceous nature. There are a number of specimens of Trochoceras gebhardi, but as a rule these are found in a rock not of the character typical of the Bertie layers bearing the eurypterids. In one case it is arenaceous and not a calcilutyte (13353 E 1682), containing two fragmentary specimens. The slabs containing the Trochoceras do not have eurypterid remains on them, with one exception (13345 E 1674) in which there is a eurypterid claw on a slab showing an imperfect T. gebhardi. Associated with the eurypterids are a number of well preserved gastropod shells belonging to a genus which is also known from the Monroe formation of Michigan. This genus is Hercynella and it is represented at Buffalo by two species H. patelliformis O'Connell and H. bufaloensis O'Connell (200).

​Seven specimens of Lingula sp. Hall occur on one of the slabs. Leperditia alta and a large number of pelecypods of the genus Goniophora, but labeled Leperditia alta occur on a slab which probably does not come from the Buffalo region, but is more likely from Ohio, judging from the lithological character. Finally, there are a number of specimens of Ceratiocaris acuminata associated on the same slabs with the eurypterids and showing a preservation as perfect as theirs, these being the only fossils which do show this. Number 11453 E 968 contains Eurypterus lacustris and a large specimen of Ceratiocaris acuminata, the former with head shield and body separated, but both beautifully preserved. The plant remains are important, for many of the specimens of Eurypterus are found lying embedded in Buthotrephis lesquereuxi, and in one case there is a large mass of Buthotrephis at the side and on top of a Eurypterus (13329 E 1657). (Some of these specimens of Buthotrephis are now regarded as graptolites.) There are three specimens of the plant ? form, Chondrites graminiformis, two of which are excellently preserved (13273 E 1602 and 13312 E 1641 Pohlman's type^[4]). At Waterville, Oneida County, New York, a small scorpion Proscorpius osborni Whitfield has been found in a good state of preservation in the Bertie waterlime.

A remarkable fact in connection with the occurrence of the eurypterids in the Bertie is their distribution in two distinct basins or "pools," the "Herkimer pool" on the east and the "Buffalo pool" on the west. These pools, while prolific in species and individuals, have, however, only two species in common, so far as published data show. Further search may reveal more forms in common, but it is certainly a significant fact that the abundantly represented species of the two areas are distinct, when the horizon is the same, and the localities only a few hundred miles distant. The following list gives the specimens for each pool, representative or identical species being apposed (39, 92 footnote):

Buffalo Pool	Herkimer Pool
1. Eurypterus lacustris	1. Eurypterus remipes
2. E. lacustris var. pachychirus
3. E. pustulosus
4. Eusarcus scorpionis
5. Dolichopterus macrochirus	5. Dolichopterus machrochirus
6. D. siluriceps	6. D. testudineus
7. Pterygotus buffaloensis	7. Pterygotus macrophthalmus
8. P. cobbi	8. P. cobbi
9. P. grandis	9. Proscorpius osborni

​"The species common to both are Dolichopterus macrochirus and Pterygotus cobbi, both of which are quite rare, while the predominant species in both places are unlike. It is not believed that these differences necessarily express distinct stratigraphic horizons, as both lie near the top of the waterlime succession, but rather indicate original regional separation into distinct lagoons or pools . . . . which we may assume to have been synchronous. There is, in the face of the difference suggested, a certain degree of approximation in the two expressed by such vicarious species as E. remipes and E. lacustris, P. macrophthalmus and P. bufaloensis, which may well mean distinctions due to geographic isolation. The Herkimer pool is well restricted and its faunule cannot be traced very far towards the west; the Buffalo E. lacustris, however, appears alone as far east as Union Springs, Cayuga County, and as far west as Bertie, Ontario. Another difference in these faunas is the preponderating great size of all the species in the Buffalo pool, and, by contrast, the small size of and abundant young among the Herkimer county species; . . . . That the smaller creatures lived in conditions of shallower water is evinced by the sun-dried and cracked rock surfaces of their matrix, while such evidences are wanting in the Buffalo pool . . . ." (39, 92). Eurypterus remipes, one of the common forms in the Herkimer pool, is also obtained from the Rondout waterlime above the Cobleskill at Seneca Falls, Seneca county, New York.

The Manlius limestone of uppermost Monroan age has yielded fragments of Eurypterus microphthalmus from various localities in New York and also from Ohio. The type, a single cephalon, came from a loose boulder near Cazenovia, Madison county, New York, containing also fragments of Spirifer vanuxemi from which the age of the boulder was determined. One nearly entire specimen was found in the drift of Onondaga Valley, near Syracuse, New York. Of the number of carapaces now in the New York State Museum, one was collected "in the town of Litchfield in Manlius limestone, not less than 100 feet above the Eurypterus horizon in the Bertie waterlime" (39, 194). Professor Whitfield's type of E. eriensis (now regarded by Clarke and Ruedemann to be the same as E. microphthalmus Hall) came from the hydraulic limestones, the Put-in-Bay dolomite, of Beach Point, Put-in-Bay Island, Lake Erie, Ohio.

There is one more Siluric fauna to be noted and that is the one in the Kokomo waterlime of Indiana. Clarke and Ruedemann, following Schuchert correlate the Kokomo with the Noblesville of ​Northern Indiana (Schuchert 255, 467), which is in turn correlated with the Lockport of New York. The latter correlation may stand, but the former is not supported by palaeontological evidence. In a private communication from E. M. Kindle, who has written quite an extensive paper on the Stratigraphy of the Niagara of Northern Indiana (139), the following comment is made in reference to the statement that the Kokomo eurypterids are found in the Lockport-Noblesville horizon: "This reference of course is an unfortunate error and is presumably based upon a correlation of the Kokomo limestone and the Noblesville limestone of Indiana which is undoubtedly erroneous. There is practically nothing in common between the faunas of the Noblesville and the Kokomo. The lithology of the beds is quite as unlike as their faunas so that there is absolutely no ground for correlating these two distinct faunas." Since Kindle has done considerable work in the region and made extensive collections of the fossils, his statement is of importance. Palaeontologically it appears that the Kokomo is surely not earlier than Salinan and is more probably Monroan, corresponding to one of the waterlimes in New York.^[5] The eurypterid remains are very thin films, scarcely more than impressions, so that scale markings often are not visible. The preservation is not nearly so perfect as in the Bertie waterlime of New York. There are at least 40 feet of limestone, characterized by thin lamination of bedding planes and the presence of eurypterids. Above this horizon is a series of limestones, not thinly laminated, containing a rather rich brachiopod fauna, but with the eurypterids the only other fossils are ceratiocarids. The brachiopod fauna, so far as is possible to learn from the literature, occurs at a different level from that in which the merostomes are found (Foerste, 67, 6–8). Four species have been reported from the merostome beds: Eurypterus ranilarva Cl. and R., E. (Onychopterus) kokomoensis Miller and Gurley, Eusarcus newlini (Claypole) and Stylonurus (Drepanopterus) longicaudatus Cl. and R., giving altogether a fairly large fauna and one that is sufficiently well preserved for purposes of characterization.

Devonic. The Devonic of America shows a great decline of the eurypterids, so far as we can judge from the fossil record, for, while in the Siluric there had been an ever-increasing number of species and of individuals, in the Devonic, on the other hand, there are no representatives in the Lower and Middle, and it is not until the very top of the Upper that a few stragglers are found. The first, a ​specifically undetermined Pterygotus mentioned by Billings, is from the Grand Greve limestone of Lower Devonic age. Remains of Pterygotus have also been found in the lower marine Devonic at Dalhousie. Finally, near Campbellton, New Brunswick, "in some indurated limestones containing fish remains of probably Upper Devonic age" are also eurypterid remains which Clarke and Ruedemann have described as Pterygotus atlanticus. An extremely incomplete and problematic form is a two-jointed fragment from the lower beds of the Portage sandstones of Italy, Yates County, New York. Originally described by Dawson as a plant (Equisetides wrightiana Dawson), it was later placed among the eurypterids by Hall as Stylonurus (?) wrightiana and is now so recognized by Clarke and Ruedemann. There is but a single fragment, part of a jointed appendage apparently. A number of fragments of Stylonurus, originally described as Stylonurus excelsior by Hall and which Beecher used in making the restoration which he called Stylonurus lacoanus, have all been united by Clarke and Ruedemann under the species Stylonurus (Ctenopterus) excelsior. There are only two specimens, one a complete carapace from the Catskill beds at Andes, Delaware County, New York, and another more fragmentary carapace from the same formation in Pennsylvania. Eurypterus beecheri Hall described from the Chemung of Pennsylvania has proved to be the same as Stylonurus beecheri.

Mississippi. From the Waverly beds of Warren, Warren County, Pennsylvania, a single eurypterid was described by Hall and Clarke in 1888 as Eurypteris approximatus. No complete description of this form is given anywhere, but the figure in the Palaeontology of New York, Volume VII, plate 27, figure 6, (106), shows the one specimen that has been found in which there are the cephalon and nine somites. This form is regarded by Clarke and Ruedemann as one of several phylogerontic species of Eurypterus which constitute the end members in different lines of development in North America and mark the decline of the race.

Carbonic. In the Carbonic (Pennsylvanic) are found four species of Eurypterus in Pennsylvania; Eurypterus (Anthraconectes) mazonensis Meek and Worthen (170) in the Coal Measures of Mazon Creek, Ill.; two species in the Carbonic of Nebraska, and two doubtful species from St. John, New Brunswick. Particular attention should be called to Eurypterus (Anthraconectes) mansfieldi which C. E. Hall has figured (98, pl. IV), showing the form just as it was found lying on ferns in a very perfect state of preservation, in the lower Productive ​Coal Measures in Beaver County, Pennsylvania. Eurypterus stylus of Hall from the Venango beds is probably the same as E. (Anthraconectes) mansfieldi, both type specimens being compressed longitudinally, but otherwise appearing the same. Eurypterus (Anthraconectes) pennsylvanicus C. E. Hall described from a single small carapace from Pithole City, Venango County, Pennsylvania is probably allied to E. mansfieldi, according to Clarke and Ruedemann (39, 428). A few fragments called by Hall E. ? potens also occur in Pennsylvania. The Carbonic eurypterids are in productive coal beds associated with plants and land animals. The fauna and flora at Mazon Creek have been especially studied by Meek and Worthen (170) from whose report the following associates of Eurypterus mazonensis are taken:

A Xiphosuran Euproöps danae M. and W.

An isopod Acanthotelson stimpsoni M. and W.

also A. eveni M. and W.

Decapoda: Palaeocaris typus M. and W.

Anthrapalaemon gracilis M. and W.

Myriopoda: Euphoberia armigera M. and W.

Arachnida: Pulmonia: Eoscorpius carbonarius M. and W.

Mazonia woodiana M. and W.

Architarbus rotundatus Scudder

Cock-roach: Mylacris anthracophila Scudder

Other insects: Miamia danae Scudder

Chrestotes lapidae Scudder

The remains from the Coal Measures of Nebraska were found by Barbour in an outcrop one mile south of Peru in the bluffs facing the Missouri River (10). The formations exposed there consist of alternating shale and limestone changing rapidly to a shale which finally merges into a massive sandstone. In this last bed there occurred a shaly band composed of thin, irregularly shaly layers, seldom half an inch thick, alternating with micaceous sand. This whole band was scarcely a foot thick and extended for over three hundred feet. Even within the band it was only the topmost two inches of the shale seams which yielded eurypterid remains. These were found in considerable abundance, forty specimens so far having been obtained in an area of as many square feet. The chitinous shells, probably representing merely the shed exoskeletons, have in all cases been reduced to carbonaceous films, but except where these are very thin they are in a good condition of preservation so that the grosser anatomy and surface markings can be seen and even some of the minute sculpturing.

​Barbour has described only one species, Eurypterus (Anthraconectes) nebraskensis. It is represented by a large number of individuals and undoubtedly as the beds are worked over a great many more specimens will be obtained. They are for the most part in good condition, though seemingly representing only the exuviæ. The individuals are small, averaging two inches in length, the largest not being even three inches long. Barbour figures and describes, but does not name a second form which he thinks may be a species different from E. nebraskensis.

The faunal associates listed by Barbour are: "innumerable leaves, stems and fragments of certain land plants, conspicuously Neuropteris pinnules, stems of Calamites, and leaf-whorls of Asterophyllites . . . . Intimately associated with the eurypterids were considerable amounts of actual plant tissue, preserved as such since Carboniferous times." (10, 507–8).

Two species, Eurypterus ? pulicaris Salter from the Little River plant bed no. 2 of St. John, New Brunswick, and Eurypterella ornata Matthew are so doubtfully identified that Clarke and Ruedemann do not consider even their eurypterid origin as certain. (39, 93) The horizon at which they were found was originally supposed to be Devonic, but is now known to be Carbonic.

Siluric. Lower Siluric Llandovery-Wenlock. The earliest eurypterid remains that have been found anywhere outside of North America, are the fragments of Pterygotus problematicus from the May Hill sandstone of upper Llandovery age, found in Eastnor Park near Ledbury, Herefordshire, England. A single chelate appendage was found associated with Nucula eastnori, Pentameri and Stricklandiniae. The Mayhill sandstone is a basal one resting by overlap upon various earlier members of the series even upon the Shineton (Dictyonema) shales at Wenlock Edge. There is everywhere a marked break and unconformity between the underlying beds and the May Hill sandstone, indicating that the latter was laid down by an advancing sea, if it was not a terrestrial (fluviatile) sandstone reworked by the sea.

In the Wenlock of the Pentland Hills, Scotland, occurs the first large eurypterid fauna of Europe. The rock containing the eurypterids is "an irregularly fissile, fine-grained sandstone, containing a ​considerable amount of structureless carbonaceous matter distributed in thin layers" (Laurie, 145, 151). The only other fossil which Malcolm Laurie found in the rock at the time of his first discovery was Dictyocaris ramsayi, but since then Peach and Horne have made a large collection of other types. In 1898 Laurie added some new discoveries from Gutterford Burn, and among these the one specimen of a scorpion, much crushed and lying imbedded in the carbonaceous matter. In the Pentland Hills the Wenlock formation is a yellowish sandstone and conglomerate, showing cross-bedding and in some places ripple marks, and is exposed in several inliers in the Old Red Sandstone, later formations having been eroded. Extensive collections have been made here by Henderson, Brown and Laurie, the latter describing a number of new species. One of the best sections is seen along Gutterford Burn, a tributary of the Esk, where the following specimens have been collected, the determinations having been made by Laurie.

Bembicosoma pomphicus Laurie.

Stylonurus (Drepanopterus) pentlandicus (Laurie).

S. (Drepanopterus) bembicoides (Laurie).

S. (Drepanopterus) lobatus (Laurie).

Eurypterus conicus Laurie.

E. minor Laurie.

Eusarcus scoticus (Laurie).

Eurypterus 3 sp. undet.

Stylonurus elegans Laurie.

S. macrophthalmus Laurie.

S. ornatus Laurie.

Slimonia dubia Laurie.

Dictyocaris ramsayi Salter.

Palaeophonus loudonensis Laurie.

Upper Siluric or Ludlow. The Ludlow of England has yielded eight species of eurypterids all in a most fragmentary condition, making it difficult to determine forms accurately. They all come from the Ludlow outcrops in Shropshire and Herefordshire. From the Aymestry limestone there are some remains which have been doubtfully referred to Pterygotus problematicus. This same species appears again and again throughout the remainder of the Siluric, being rare in the Upper Ludlow group, but becoming more common towards the top of the Temeside group in the Ludlow district. Eurypterus acuminatus Salt. and E. linearis are rare in the Upper Ludlow, the former ​occurring also in the Temeside group. Eurypterus pygmæus Salt. and Stylonurus megalops Salt. are common as fragments in the higher olive shales of the Temeside group. Pterygotus banksii Salt. together with numerous indeterminable species of Eurypterus are found in the Ludlow Bone-Bed; this species is also common in the Platyschisma bed and the upper olive shales of the Temeside group; in the same shale P. ludensis Salt. is abundant. In all cases where species are reported to be common it is to be remembered that no entire specimens are found but only fragments and disjecta membra. The occurrences cited are from the Ludlow district in Shropshire; to the south-west in the Downton Castle sandstone at Kington in Herefordshire Pterygotus banksii has been found in large numbers associated with P. gigas, the spines of crustacea and fish and also Platyschisma helicites and Lingula cornea. Salter has further described Eurypterus abbreviatus from a single telson which he found at Kington. Brodie collected specimens of Pterygotus banksii, Eurypterus pygmaeus, E. acuminatus, and E. abbreviatus at Purton, Herefordshire. The greatest abundance of specimens is found in a sandy marl lying just below a yellow sandstone containing plants, seed-vessels of Lycopodiaceae and fragments of eurypterids. The horizon is about that of the Ludlow Bone-Bed (24, 236).

The Ludlow of Scotland is found only in a few inliers in Lanarkshire. Division 3 recognized by Peach and Horne (215) consists of flagstone and greywackes with Ceratiocaris beds and containing the Ludlow fish band. From these beds Slimonia acuminata Salter has been described associated with five species of Ceratiocaris and worm tracks. From the same shales Pterygotus bilobus Salter and the common Ludlow fish Thelodus scoticus are reported. In certain places occur Beyrichia kloedeni and Platyschisma helicites forms very frequently associated with Upper Siluric eurypterids. The fish band contains Slimonia acuminata, the myriopod Archidesmus loganensis Peach, four species of the phyllocarid crustacean Ceratiocaris and one of Physocaris, together with numerous fish fragments and two species of Thelodus. Of great interest has been the discovery by Peach in this fish band of one of the oldest scorpions from Great Britain, Palaeophonus caledonicus Hunter. This is approximately the same horizon at which Lindström found Palaeophonus nuncius in Gotland (see below, p. 34). The eurypterid horizon par excellence occurs in the next higher division above the fish band and contains Eurypterus lanceolatus (Salt.), Eusarcus obesus (Woodw.), E. scorpioides (Woodw.), ​Pterygotus bilobus Salt., together with three varieties of this species, P. raniceps (Woodw.), Slimonia acuminata (Salt.) and Stylonurus logani (Woodw.). The Pterygotus beds are followed by the "Trochus," more properly, Platyschisma beds which correspond to the beds of the same name in England, and which contain fragments of Slimonia acuminata as do the next overlying beds which mark the transition into the sandy Lanarkian series.

The Lanarkian. About 1400 to 1500 feet above the base of this series occurs a fish-band in the carbonaceous shales of which Eurypterus dolichoschelus (Laurie) has been found associated with Ceratiocaris, five species of fishes, and Pachytheca and Parka. At another locality seven species of fishes, Ceratiocaris, Dictyocaris, Pachytheca, a Myriopod and Eurypterus dolichoschelus (Laurie) and Stylonurus ornatus (Laurie) have been found.

Devonic. The Devonic formations of Great Britain have a better representation of eurypterids than have those of North America. The Old Red Sandstone of Forfarshire has yielded Pterygotus anglicus in abundance and in a good state of preservation and one nearly entire specimen of P. minor. From the same region come three species of Stylonurus, S. scoticus, S. powriei, S. ensiformis, and finally the little known Eurypterus brewsteri. In the Old Red Sandstones of England occur Eurypterus pygmaeus and Stylonurus symondsii. Fragments of Pterygotus problematicus have been reported from the Lower Old Red of the Ludlow district. A few fragments of Eurypterus hibernicus Baily have been found in the Upper Old Red of Kiltorcan, Kilkenny County, Ireland. There are thus ten species of eurypterids from the Devonic of Great Britain, all occurring in the Old Red Sandstone facies of deposits associated with fishes, land plants, fluviatile molluscs, myriopods and crustacea, such as the fresh or brackish-water phyllopod, Estheria, the ostracod Beyrichia and certain phyllocarids. With the exception of Pterygotus anglicus none of the eurypterids is either abundant or well preserved, most of the species being represented by a single portion of the exoskeleton or by a number of fragments. Moreover, these fragments are scattered in occurrence geologically and geographically. Six species are found in Forfarshire, Scotland, in the Lower Devonic (Caledonian); three species are sparingly represented in Brecknockshire and Herefordshire, England, at the same horizon; while a few fragments of a single species occur in the Upper Old Red of Ireland.

Mississippic or Calciferous. The Calciferous fresh-water ​limestone of Scotland, equivalent in age to the Mississippic of North America, has yielded three species of Eurypterus: scabrosus, Woodward, scouleri Hibbert and ? stevensoni Ethridge. Of the first species a doubtful fragment has been reported from Eskdale, Scotland. Hibbert was the first to describe as a Eurypterus the two nearly complete individuals and three or four fragments found in the Burdiehouse fresh-water limestone at Kirkton, near Bathgate, West Lothian. The organic remains are scattered through in no regular order and are not confined to the limestone particularly, but occur in the sandy beds above and below, not in particular seams. One of the eurypterid remains had earlier been described under the name Eidothea, but Hibbert rightfully called it Eurypterus scouleri (116, 280, 281, pl. XII). Vegetal matter is diffused through the limestone and in this fossil plants are well preserved, the form particularly abundant being Sphenopteris affinis. Microscopic Entomostraca abound which have been named by Hibbert Cypris scoto-burdigalensis, and a microscopic mollusc approaching Planorbis also occurs. Fish remains are abundant: Gyracanthus farmosus Agassiz, ganoid and sauroid teeth, and many coprolites are found. Woodward says of this limestone: "it is a fresh water deposit, and abounds in bands of silex alternating with calcareous matter and presents all the appearance of having been deposited by thermal waters during the Carboniferous epoch" (312, 180). The third species above referred to was described by Etheridge from a few fragmentary spines found in a light-colored micaceous sandstone of the Cement-stone group in Kimmerghame quarry, near Dunse in Berwickshire, Scotland. In the same shire Peach has recently discovered some fragments for which he erected the genus Glyptoscorpius, a eurypterid which had combs, and walking feet ending in two claws. In the Calciferous sandstone here at Lennel Braes, near Coldstream, Berwickshire, a specimen of G. perornatus Peach showing five body segments much broken, and a number of combs, referred to G. caledonicus (Salter) have been found. Besides these, are a number of fragments referred to the genus Glyptoscorpius, but specifically unidentifiable (209, 516–525). At the River Esk, four miles south of Langholm, Dumfriesshire, the two species of Glyptoscorpius are found with the following associates: several species of Phyllocarida, Ceratiocaris scorpioides Peach, C. elongatus Peach; Peracarida, Anthrapalaemon etheridgei Peach, A. parki Peach, A. traquairii Peach, A. macconochii, A. formosus Peach, Palaeocrangon eskdalensis Peach, Palaeocaris scoticus Peach, and later discoveries ​have added Pseudo-Galathea rotundata and Palaeocrangon elegans. At Tweeden Burn, Liddesdale, have been found many membra disjecta, unidentifiable. The fauna also includes some Xiphosurans: Prestwichia alternate Peach from Lavuston Burn, upper Liddesdale, Prestwichia rotundata Woodward from the River Esk locality and Cyclus testudo Peach from Langholm. Many of these crustacean forms are quite well preserved. Scorpions also occur at Langholm: Eoscorpius glaber Peach, E. euglyptus Peach and E. inflatus Peach. These forms though never perfect are very complete and show all parts well.

Carbonic or Carboniferous. In the Coal Measures of Great Britain the final stragglers among the eurypterids are found, just as they are in North America. Eurypterus (Arthropleura) mammatus Salter includes fragments from Pendleton Colliery, near Manchester, England, which are associated with many plant remains, a few of which may be mentioned:

Lepidodendron obovatum.

Lepidodendron sternbergii.

Lepidodendron elegans.

Neuropteris loshii.

Neuropteris heterophylla.

Neuropteris gigantea.

Cyclopteris flabellata.

Sphenopteris obtusiloba.

Sphenopteris latifolia.

and some others

Siluric. Lower Siluric Ee₁, Ee₂ of Barrande. From the Siluric basin of Bohemia Barrande listed six species of Pterygotus, all of which are represented by the merest fragments and are of rare occurrence. They are found in undoubted marine formations, for Ee₁ is a black graptolite-bearing shale, while Ee₂ contains numerous cephalopods, gastropods, trilobites and corals (12, 39–44). The species of Pterygotus are: bohemicus, comes, cyrtochela, kopaninensis, mediocris and nobilis. Of the general preservation and faunal associates of these eurypterids Barrande remarks:

"Our basin, so privileged in respect to the frequency and the state of preservation of the trilobites and the other crustacea, appears, on the contrary, very poor in the fossils representing the two types of ​eurypterids, which are recognized in our formations. (Pterygotus and Eurypterus).

". . . . Far from finding individuals complete and well preserved, it will prove difficult to add any new facts of importance to those already published on the organization of the species of this type.

"That advantage is not reserved for us, for the Silurian basin of Bohemia, so favored in all other respects, is relatively poor in fossils of the genus Pterygotus, not only because of their great rarity, but also because of the reduction of the specimens to little fragments. Since almost all of the remains are found in the large horizon of the Cephalopods, that is, in our limestone band e 2, it seems to us that one may attribute the almost total disappearance of these gigantic Crustacea to the voracity of these molluscs, against whom they were forced to maintain the struggle for existence." (13, 556).

We need not consider seriously this interpretation of the fragmental character of the eurypterid remains as they can be interpreted in another manner (see p. 199).

Semper (261) has recently done some work in the region and has revised and added to Barrande's original species. In e₁ β at Podol Dvorce, near Prague, he has collected a few fragments to which he has given the name Pterygotus barrandei of which there are also some fragments at Dlouhá hora, in horizon e₂. A few endognathites from the former locality have been described as P. beraunensis Semper, since they come from near Beraun. Some fragments of a swimming foot are also described by Semper from e₂, as P. blahai, in a thinly laminated limestone rich in Orthoceras which occurs at Viŝňovka near Lochhov. Of all the species found in Bohemia the best one is a fragmentary individual showing the head with the first eight somites attached, and a few separate fragments, these constituting the species Eurypterus acrocephalus Semper from horizon e₁, at Dvorce. From these various occurrences it is apparent that the eurypterids, though represented by a large number of species in the beds of Wenlock or Niagaran age of Bohemia, are found only rarely and in a most fragmentary condition, although the large marine fauna occurring in the same horizon is one of the largest and most perfect that is known, forming the basis for Barrande's ponderous work on the Système Silurienne in which many volumes are devoted to the description and figuring of the marine fossils, while a very little space suffices for the meagre eurypterid fauna. Barrande notices in a paper on the ​correlation of the Siluric deposits of Bohemia and Scandinavia (Parallele entre les Depôts Siluriens de Bohême et de Scandinavie (11), that Pterygotus remains have been found at Klinta in Scania, southern Sweden, which recall Pterygotus problematicus of England (11, 58)

Upper Siluric or Ff₁ of Barrande. Two species of Eurypterus have been recorded from the Upper Siluric of Bohemia in the same incomplete condition that those from the Lower were found in. E. pugio Barrande and a species related to P. bohemicus Barrande are the only representatives in this period. The latter is reported by Semper from a single claw and part of an abdomen found at Cerná rockle, Kosoř in a black limestone of Ff₁ age.

Carbonic. Coal Measures of Bohemia. In a rather blackish grey shale at Wilkischen, near Pilsen, Reuss found two macerated, but nearly complete individuals and a cephalon of a eurypterid which he named Eurypterus imhofi, and which is associated on the same slab with pinnules of Pecopteris. Reuss says that this fossil "of the Bohemian Coal Measures—a freshwater formation—is without doubt derived from a freshwater or brackish water ancestor (228, 83)."

Devonic. Upper Devonic. In only one locality in Belgium have eurypterids been found. Some thirty kilometers southwest of Liege at Pont de Bonne near Modave is exposed a section showing the Upper Devonic sandstones of Condroz. Lohest, Braconier and Destinez in working up this section found a few eurypterid fragments in 1888 and in the following year these were described by Julien Fraipont and Maximin Lohest. Eurypterus lohesti was described by Dewalque from two specimens, one the counterpart of the other, representing a complete cephalon. Fraipont described, Eurypterus ? dewalquei from a cephalon, a portion of an abdominal segment, and a few other fragments. One other fragment, a portion of one of the appendages, is thought by Fraipont to belong to a species related to E. ? dewalquei, but because of the similarity in ornamentation and agreement in size, he makes it only a variety, calling it E. ? dewalquei var. longimanus.

The beds in which these remains were found are described by Lohest as follows (68, 55):

"We procured the major part of our fossils from the bed of green shales. They contain: Glyptolepis multistriatus, G. radians, ​Holoptychius dewalquei, Eurypterus, Spirorbis. Mr. Destinez found a beautiful Ichthyolite which is probably new. We cite again: lamellibranchs, lingulas, ferns and Lepidodendron. That bed contains sometimes thin layers of sandstones, on which one finds associated on the same planes of stratification lingulas, lamellibranchs, ferns, and ganoid scales. Mr. I. Braconier has collected excellent specimens which demonstrate the certainty of this fact.^[6] . . . .

"In beds F, G, H, I, we have not collected any determinable fossils; but in the lower part of bed J we have found vegetal matter, scales of the fish, Holoptychius inflexus, a small species of Pterichthys and the remains of a Dipterus as I have pointed out." (Fraipont, 68, 55).

A little lower in the series in bed B impressions have been found which suggest those of rain-drops, also very numerous axes of vegetal matter probably, as suggested by Mr. Mourlon, stipes of the fern Palaeopteris hibernica, and in the same bed Mr. Destinez found a large bone, belonging apparently to a fish.

Siluric. Upper Siluric of Gotland. The Baltic Isles have long been famous for their Siluric sections which are so excellently shown on Gotland. The lowest eurypterid horizon is found in the Pterygotus marl of Gotland of Upper Siluric age. Although the sections in the northern and southern parts of the island have been studied separately and the correlations are not as yet complete, still one important fact has stood out for the whole island: there is everywhere a great break between the Lower and Upper Gotlandian (Siluric), indicating in many places that there was at this time a retreat and a subsequent advance of the sea. In the north around Visby, Hedström (113) has recognized seven subdivisions of the Gotlandian. Beginning at the base, the first bed to be shown along the shore is the Stricklandia marl (I of Hedström), with Palæocyclus as the characteristic fossil. Then follows II, a marly limestone showing reef masses at intervals and containing a Niagaran fauna. The succeeding beds (III) are of particular interest to us. At the base are 3 meters of yellowish grey limestone with crinoids, and then follow 16 meters of grey marls interstratified with limestone, the upper 5 meters of which consist of stratified limestones, oolitic at the base, but becoming gradually coarser towards the top where they are conglomeratic, and where ​ripple-mark structures are sometimes observable. Above these strata comes a complex of layers, one meter thick, consisting of marl shales and limestones with Pterygotus osiliensis and Palæophonus nuncius, a scorpion. Lindström has called this thin stratum the Pterygotus marl, and it is seen to lie just at the top of III.^[7] Here there is a break and disconformity, above which follows a conglomerate (IV) with waterworn gastropoda and portions of Spongiostroma holmi Rothpletz. The relations of the reef limestone and marl are well shown in the vicinity of Visby. The reefs are composed of non-stratified accumulations of Stromatoporæ mainly, with a few corals in addition. Between the reefs of II are the finely stratified bituminous, brownish shales of III, well shown on the island of Karlsö west of Visby, which contain a marine and estuarine fauna mixed.

Upper Siluric of Oesel. This island has yielded a large crustacean fauna in the usual association with eurypterids. Two species of Eurypterus are reported: E. laticeps Schmidt from two fairly perfect head shields, and E. fischeri Eichwald from many excellent specimens. There is also an abundance of fragments of Pterygotus osiliensis. The bed in which these occur is a fine grained Platten-kalk or dolomite, with a peculiar fauna throughout; this is followed by other granular limestones containing the usual uppermost Siluric fauna. The Eurypterus beds have a fairly wide extent in western Oesel, but the fullest development of the fauna is seen only near Rootziküll, on the west coast of the island, in the parish of Kielkond. Here the beds are a dolomite in which the chitinous exoskeletons of Pterygotus and Eurypterus have been excellently preserved, and even the tail sting of a Ceratiocaris and the shields of two cephalaspid fishes, Thyestes verrucosus Eichw. and Tremataspis schrenckii Schmidt, and the shells of the little Lingula nana Eichw. have been found. Rather rarely occurring are the Hemiaspidae: Bunodes lunula Eichw., B. rugosus Nieszk. and schrenckii Nieszk. sp. as well as Pseudoniscus aculeatus Nieszk. and the shells of Orthoceras tenue Eichw. Bunodes and Leperditia are represented by many specimens, but these and all the other fossils mentioned show, in place of the shell which is destroyed, only a black carbonaceous film representing the organic material (Schmidt 248, 28). The eurypterids do not show the same kind of preservation, for Schrenck (254, 35) reports the integuments of Eurypterus remipes Dekay (with which E. tetragonophthalmus Fischer is synonymous and which Schmidt has since placed under E. fischeri,) to be entirely unaltered, not only chemically, still ​remaining pure chitin, but also in their entire internal make-up and with their original color such as is characteristic of living representatives.

Siluric. Upper Siluric of Podolia and Galicia. From various localities, mainly in Galicia, Austria, but occasionally from Podolia, Russia, a few fragments of Eurypterus fischeri are reported, together with specimens determined with difficulty to be Pterygotus osiliensis, and also three telsons of specifically unidentifiable Stylonurus.

Devonic. Middle Devonic of Galicia. A single telson of a Pterygotus species has been found by Siemiradzki in the Devonic coral limestone of Skala, Valencia (263).

Siluric. Upper Siluric. Professor McCoy has reported (168) the finding by Mr. F. Spry of four eurypterid remains in the Upper Silurian rocks underlying Melbourne. These rocks have been correlated by McCoy with the Victorian series. The matrix in which the merostome fragments were found is described as resembling very closely the black flaggy layers of the uppermost Ludlow of Lesmahagow, Scotland, while the eurypterid found there seems to have its closest affinities to Pterygotus bilobus. The specimen figured is fragmentary, but apparently of a eurypterid, which McCoy has referred to Pterygotus australis.

Carbonic. Middle Saarbrücker. In the Saarbrücken "basin" of Germany the Carbonic has been divided into two parts, the upper or Ottweiler with grey and red sandstone at the top and grey shale and sandstone below containing Pecopteris arborensis, Estheria, Leaia baentschiana and fish remains; and the lower or coal-bearing Saarbrücken beds containing in their middle members abundant plant remains and two eurypterid species. Arthropleura armata Jordan is represented by two or three abdominal segments found in the beds in the Friedrichsthal tunnel two miles from Saarbrücken, where in the same beds are plant remains of Lepidophyllum lineare Brong., and Anthracosaurus raniceps, Dictyoneura blattina and other insects. In the railroad shaft at Jägersfreude, ¾ of a mile from Saarbrücken, one incomplete individual of a form called by Jordan Adelopthalmus (Eurypterus) granosus has been found (135).

​

Carbonic. Coal Measures of Brazil. David White described some fragments from the Santa Catharina system, about 55 meters above the granite floor (Tubarão series) or 225 meters below the Iraty black shale (Passa Dois series) northeast of Minas, Santa Catharina, Brazil (297, 229, 589, 605). The fragments are of most doubtful identification, some being apparently plant remains, but others having a suggestion of relation to the Eurypterida (297, pl. XI, figs. 4, 6, 7, 8). These are described as Hastimima whitei White.

Devonic. Witteberg series. From the Upper Devonic Witteberg series of Cape Colony, South Africa, Professor A. C. Seward has described two fragments of a fossil which he considers to be a eurypterid. He compared it with the species described by David White from Brazil and called it Hastimima sp., saying: "The view which seems to me most hopeful is that this fossil represents part of a bodysegment of a Eurypterid" (262, 485). Seward sent the specimens to Woodward who not only concurred in the opinion as to the eurypterid nature of the remains, but he also considers that the Brazilian forms are eurypterids (325, 486). It is gratifying to note that the opinion expressed by these earlier writers is fully supported by Clarke and Ruedemann in their monograph where they have discussed this genus (39, 400–406) and figured some more of the fragments from Brazil.

The Witteberg series consists of a hard blue micaceous quartzite, replaced in some localities by shale or slate. So far as known it is unfossiliferous except for occasional plant stems allied to Lepidodendron and the widespread markings known as Spirophyton caudagalli. A photograph of this fossil given by Hatch and Corstorphine in their Geology of South Africa (111, fig. 22.) reveals no essential difference between it and the Spirophyton caudagalli of the Esopus, Oriskany and Hamilton of eastern North America. Seward considers that it is an inorganic structure and Grabau has gone even further in suggesting that it is due to the blowing back and forth of reed-like plants on a plastic surface capable of holding such markings long enough until covered over by wind-blown dust or sand. At any rate, the formation is undoubtedly non-marine, and the two eurypterid fragments therein could hardly have come from any other source than the land waters.

​ ​ ​

Permic. About a third of the way south from Porto to Lisbon and about 40 km. in from the coast lies Bussaco, famous for its Carboniferous rocks and the abundant flora therein. This region was studied as long ago as 1850 by Carlos Ribeiro. Three years later a symposium on the sections and fossils of Bussaco appeared in the Quarterly Journal of the Geological Society of London, and then in 1890 Wenceslau de Lima made a very complete study of the region, with the result that, after a careful identification of the flora, he was able to show that certain of the beds are Permic in age, belonging to the lower Rothliegende. During his investigations he found a single small eurypterid, the cephalon, body segments and telson intact, though all of the appendages are missing. The animal measures 32.5 mm. in length, has a large cephalon, a bulging body made up of seven somites and a long tail formed by the last seven segments. To this form he gave the name Eurypterus douvillei. Associated with this eurypterid are the plants Walchia piriformis and Sphenophyllum thoni. The beds in which these fossils are found are a series of shales, sandstones and conglomerates from the abundance of which de Lima argues that torrential conditions must have obtained at the end of the Carbonic and beginning of the Permic (149, 151). A glance at Koken's world map showing the relation of land to sea during the Permic will show that Bussaco was in position to receive very heavy torrential deposits, being near the coast of that time.

All of the data of the foregoing pages are summarized in the following series of tables. Table I is designed to show quickly in what horizons and country any species of eurypterid has been found. Table II, summarizing Table I, gives at a glance the numbers of species that are recorded from each horizon and from each country and also from each period. Table III gives in greater detail the localities in which remains have been found, but is particularly meant to give an accurate description of the mode of occurrence of every species, if the remains are fragmentary, to state how many fragments have been found, and if perfect to record with equal care the numbers found. Each table is complete in itself, but all three, on the other hand, should be used together since each one supplements the others.

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species		horizon and facies		locality	condition
1. Beltina danai		Greyson shales, Belt Terrane		Montana	Hundreds of fragments; surface markings absent generally.
		Alty limestone		Altyn, Montana; Johnson Creek, Alberta, Canada	Numerous fragments, some showing scale markings
2. Bembicosoma pomphicus		Wenlock shales and sandstones		Gutterford Burn, Pentland Hills, Edinburghshire, Scotland.	Two incomplete individuals
3. Dolichopterus breviceps		Normanskill shales and sandstones		Broom Street Quarry, Catskill, New York	A single carapace
4. D. frankfortensis		Schenectady shale		Schenectady (Dettbarn Quarry), Aqueduct, Rotterdam Junction Duanesberg, New York	About a dozen carapaces
5. D. laticeps		Zone K, Eurypterus waterlimes of Oesel		Rootziküll, Oesel	Two head shields
6. D. latifrons		Schenectady shale		Schenectady, New York	Two incomplete carapaces
7. D. macrochirus		Bertie waterlime		Williamsville, Lichtfield, Waterville, New York	Three nearly complete individuals; a few fragments
8. D. otisius		Black shales in Shawangunk grit		Otisville, New York	About 30 carapaces some showing two attached tergites
				Delaware Water Gap, Pa.	A number of carapaces
9. D. siluriceps		Bertie waterlime		Williamsville, New York	A single carapace
10. D. stylonuroides		Black shales in Shawangunk grit		Otisville, New York	Three carapaces, and one specimen with carapace, swimming leg and three tergites
11. D. (?) testudineus		Bertie waterlime		Lichtfield Herkimer Co., New York	A single carapace
12. Echinognathus clevelandi		Utica shale		Holland Patent, Oneida Co., New York	Fragment of a thoracic segment
13. Eurypterus abbreviatus		Downtown Castle sandstone		Kington, Herefordshire, England	One incomplete telson
14. E. acuminatus	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Spirifer elevata shales, upper Ludlow group	${\displaystyle \left.{\begin{aligned}\\\\\end{aligned}}\right\}}$	Ludlow railroad cut, Ludlow, Shropshire, England	Several incomplete telsons and rare fragments
		Olive shales of Temeside group
15. E. approximatus		Waverly		3 mi. s. of Warren, Warren Co., Pennsylvania	A single specimen with carapace and nine somites

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16. E. brewsteri		Arbroath flags, Caledonian Old Red Sandstone	Kelly Den, near Arbroath, Forfarshire, Scotland		A carapace, portion of first thoracic segment; ovisac
17. E. brodiei		Lower part of Downton Castle sandstone	Purton, near Stoke Edith, Herefordshire, England		One almost entire individual and some fragments
18. E. cephalaspis		Downton sandstone	Kendal, Westmoreland, England
19. E. chadwicki		Normanskill shales and sandstones	Broom Street Quarry, Catskill, New York		A single carapace
20. E. conicus		Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Edinburgshire, Scotland		A number of more or less complete individuals; limbs fragmentary.
21. E cyclophthalmus		Wenlock shales and Sandstones	Gutterford Burn, Pentland Hills, Edinburgshire, Scotland		One specimen showing part of carapace and parts of all body segments
22. E. dekayi		Bertie waterlime	Near Buffalo, New York		Two nearly complete specimens
23. E. ? dewalquei		Famennian sandstone	Condroz, Belgium		Portion of cephalothorax and a few fragments
24. E. ? deqalquei var. longimanus		Famennian sandstone	Condroz, Belgium		Last segment of an appendage
25. E. dolichoschelus	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Ludlow fish band	Dippal Burn, Greenock Burn, etc., Lesmahagow Lanarkshire, Scotland	${\displaystyle \left.{\begin{aligned}\\\\\\\end{aligned}}\right\}}$	Numerous fragments
		Ghuconome shale in div. 9, P & H.	Hagshaw Hills, Lanarkshire, Scotland
		Lanarkian, div. 9, Peach & Horne	Dippal Burn, Lesmahagow, Scotland
26. E. douvillei		Rothliegende sandstone	Bussaco, Portugal		One almost complete individual, well preserved, appendages absent
27. E. fischeri		Zone K Eurypterus waterlimes of Oesel	Rootziküll, Wita, Attel, etc. Oesel		Large numbers preserved entire with unaltered chitin.
		Zone K Eurypterus waterlimes of Oesel	Lodjal, S. E. Oesel		Traces
		Upper Siluric limestone of Podolia	Kamieniec podolski, Dumanow, Zawale, Studzienica, Zaluczs, all in Podolia		Fragments only
28. E. fischeri var. rectangularis		Zone K Eurypterus waterlimes of Oesel	Rootziküll, Oesel		Occasional incomplete specimens; carapace with two tergites and 2 appendages
29. E. hibernicus		Kiltorcan sandstones and flagstone, Upper Old Red	Kiltorcan, Kilkenny Co., Ireland		Nearly a dozen fragments, including 2 carapaces, 2 or 3 somites, fragments of appendages
30. E. imhofi		Roof shale in Carbonic of Bohemia	Wilkischen, near Pilsen, Bohemia		Several nearly entire individuals; well preserved

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species	horizon and facies	locality	condition
31. E. lacustris	Bertie waterlime	Williamsville and Buffalo, New York; Bertie, Ontario	Well preserved specimens abundant
		Black Rock, Erie Co., Union Springs, Cayuga Co., New York	A few smaller specimens
32. E. lacustris var. pachychirus	Bertie waterlime	Buffalo, Erie Co., New York	An abdomen, two swimming legs several endognathites
33. E. lanceolatus	Pterygotus beds, div. 4 of Ludlow (Peach & Horne)	Lersmahagow, Lanarkshire, Scotland	Several nearly entire individuals and fragments
34. E. liniaris	Spirifer elevata shales, Upper Ludlow group	Ludford, S. of Ludlow, and Kington, Herefordshire	Telsons only
35. E. lohesti	Famennian sandstone	Condroz, Belgium	One carapace
36. E. maria	Black shales in Shawangunk grit	Otisville, Orange Co., New York	Abundant, well preserved, though incomplete; mostly immature; carapaces numerous
		Delaware Water Gap, Pa.	Several carapaces
	Olive shales in Tuscarosa sandstone	Swatora Gap, Pa.	Several small carapaces
E. microphthalmus	Manlius limestone	Cazenovia, Madison Co.; Onondaga Valley, Lichtfield, Jerusalem Hill, Herkimer Co.
	Monroe (Put-in-Bay) limestone	Put-in-Bay Island, Lake Erie	Two cephala
38. E. minor	Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Edinburgshire, Scotland	One nearly entire individual, a carapace and fragments
39. E. moyseyi	Clay nodules in Coal measures	Northwest Ilkeston, Derbyshire, England	Two specimens, posterior abdominal segments missing
40. E. pittsfordensis	Pittsford shale	Pittsford, Monroe Co., New York	Rare and fragmentary; a few nearly complete individuals
41. E. pristinus	Schenectady shale	Dettbarn Quarry, Schenectady, New York	One carapace and doubtful patches
42. E. ? (Dolichopterus?) prominens	Clinton sandstones	Cayuga Co., New York	A single carapace
43. E. pustulosus	Bertie waterlime	Buffalo, New York	Two carapaces and one postabdomen, all fragmentary

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44. E. pygmaeus		Downton Castle sandstone		Kington, Herefordshire, England	Carapace and portion of body; scattered fragments
		Olive shales, Temeside group		Ludford Lane and Ludlow railroad cut, Herefordshire, England	Fragmentary individuals common
45. E. ranilarva		Kokomo waterlime		Kokomo, Indiana	A few nearly complete; rare and poorly preserved
46. E. remipes		Bertie waterlime		Waterville, town of Westmoreland, Oneida Co.; Jerusalem (Wheelock's Hill, Lichtfield, Herkimer Co.; Cedarville and Paria Hill, Herkimer Co.; near Oriskany, Cayuga junction, Cayuga Co., N. Y.	Numerous well preserved and many fragments
		Rondout waterlime		Seneca Falls, Seneca Co., New York	Typical specimens well preserved
47. E. ruedemanni		Schenectady shales		Near Rotterdam Junction, Schenectady Co., New York	A single carapace
48. E. scouleri		Burdie House limestone		Kington, near Bathgate Linlithgowshire, Scotland	Two carapaces and a few fragmentary abdomina
		Upper Old Red Sandstone		Kiltorcan, Kilkenny Co., Ireland	Three patches of integument; very doubtful
49. E. cf. scouleri		Coal Measures of Silesia		Near Neurode, County of Glatz, Silesia	One incomplete carapace and two fragments of appendages
50. E. ? (Dolichopterus?) stellatus		Schenectady shales		Dettbarn Quarry, Schenectady, New York	Incomplete carapace and patches of integument
51. E. ? stevensoni		Cement stone group lowest Calciferous		Kimmerghame Quarry, Blackadder Water, near Dunce, Berwickshire, Scotland	Three fragments of body segments showing sculpturing
52. E. wilsoni		Downton sandstones		Ludlow's Pit, Radstock, Somersetshire, England	First six body segments only
53. E. sp. Barbour		Coal measures		One mile south of Peru, Nebraska	One almost complete individual
54. E. sp. Elles and Salter	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Chonetes striatella beds	${\displaystyle \left.{\begin{aligned}\\\\\\\end{aligned}}\right\}}$	Ludlow district, Shropshire and Herefordshire	Various unidentifiable fragments probably representing several species of Eurypterus; rare in two lower horizons, common in the higher
		Ludlow Bone-Bed
		Downton Castle sandstones
		Temeside shales
55. E. sp. Peach and Horne		Wenlock shales and sandstones		Near Straiton, Girvan, Scotland	Fragments

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species		horizon and facies	locality	condition
56. E. sp. Laurie	${\displaystyle \left.{\begin{aligned}\\\end{aligned}}\right\}}$	Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Edinburgshire, Scotland	Numerous unidentifiable fragments
57. E. sp. (?) Laurie
58. E. sp. Moberg		Ove I-Ramsåsa formation Zone I	Bjersjölagård, Sweden	Abudant fragments
59. E. (Adelopthalmus) granosus		Middle Saarbrücker Schiefer	RR. shaft at Jägersfreude, ¾ mi. from Saabrücken, Germany	One incomplete individual
60. E. (Anthraconectes) mansfieldi		Carbonic shale below Darlington cannel coal	Near Cannelton, Darlington Township, Beaver Co., Pennsylvania	Several nearly complete and a number of fragments
61. E. (Anthraconectes) mazonensis		Coal Measures (Alleghany)	Mazon Creek, Grundy Co., Illinois	Single ventral impression of incomplete individual
62. E. (Anthraconectes) nebraskensis		Coal measures	One mile south of Peru, Nebraska	Abundant and well preserved; some only carbonaceous films
63. E. (Anthraconectes) pennsylvanicus		Arenaceous shale in Coal Measures	Rooker Farm, Pithole City, Venango Co., Pennsylvania	A single small carapace
64. E. (Onychopterus) kokomoensis		Kokomo waterlime	Kokomo, Indiana	One nearly perfect and well preserved; three fairly good specimens
65. E. (Tylopterus) boylei		Guelph dolomite	Ontario, Canada	A single incomplete though well preserved individual
66. Eusarcus acrocephalus		Ee1 Kuchelbade graptolite sh.	Dvorec, near Prague, Bohemia	Carapace and first eight body segments; better preserved than other specimens in same bed
67. E. (?) cicerops		Black shales in Shawangunk grit	Otisville, New York	Rare; several carapaces and a preabdomen
68. E. linguatus		Normanskill shales and sandstones	Broom Street Quarry, Catskill, New York	Two fragmentary carapaces
69. E. logani		Eramosa beds, Niagaran	Eramosa river, near Guelph, Ontario, Canada	Numerous fragments very poorly preserved; post-abdominal segments, spines, telsons, a metastoma

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70. E. (?) longiceps		Schenectady shale	Schenectady, New York		A number of carapaces; one with frag mentary preabdomen attached
71. E. newlini		Kokomo waterlime	Kokomo, Indiana		Four nearly complete, poorly preserved, showing later growth stage
72. ? E. obesus		Trochus or Platyschisma beds (5 of Peach and Horne)	Lesmahagow, Lanarkshire		One almost entire, and fragments
73. E. punctatus	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Upper Ludlow	Whitcliff, near Ludlow, Herefordshire, Kendal, Westmoreland, England	${\displaystyle \left.{\begin{aligned}\\\\\\\end{aligned}}\right\}}$	Detached appendages and fragmentary remains Five abdominal segments and fragments
		Lower Ludlow	Church Hill, Leintwardine, Shropshire, England
		Wenlock limestone and shale	Dudley, Worcestershire, England
74. E. aff. punctatus et acrcocephalus		Ee1 β Kuchelbader graptolite shales	Podol Dvorce, Bohemia		A single endognath
75. E. raniceps		Div. 3 (Peach and Horne) Ceratiocaris beds	Logan water, near Lesmahagow, Lanarkshire, Scotland		One incomplete and fragmentary individual
76. E. scorpioides		Div. 3 (Peach and Horne) Ceratiocaris beds	Logan water, near Lesmahagow, Lanarkshire, Scotland		One nearly complete individual
77. E. scorpionis		Bertie waterlime	Williamsville and Buffalo, New York		Twenty specimens, 7 nearly entire, one of a young individual
78. E. scoticus		Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Edinburgshire, Scotland		Numerous fragments
79. E. simonsoni		Zone K, Eurypterus waterlimes of Oesel	Quarry at Wita, near Rootziküll, Oesel		One incomplete individual and one fragment of a foot
80. E. triangulatus		Schenectady shale	Dettbarn Qurry, Schenectady, New York		Three incomplete specimens, 3 carapaces, one preabdomen
81. E. vaningeni		Dark shales 21 feet below base of Vernon shales	Near Farmer's Mills, Oriskany Creek, 3 mi. S. of Clinton, New York		Two carapaces; a few fragments, and one carapace with nearly complete preabdomen
82. Glyptoscorpius caledonicus		Calciferous sandstone	Lennel Braes, Coldstream and Cockburnspath, Berwickshire, Scotland		Combs only
83. G. perornatus		Calciferous sandstone	River Esk, 4 mi. S. of Langholm, Dumfriesshire, Scotland		Carapaces with 5 body segements attached; specimen incomplete
84. Hastimima whitei		Santa Catharina system	N. E. of Minas, Santa Catharina, Brazil		Three fragments of integument showing surface markings
85. H. sp. Seward		Witteberg shales	Cape Colony, South Africa		One fragment of body segment showing surface markings

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species		horizon and facies		locality		condition
86. Hughmilleria magna		Schenectady shale		Dettbarn Quarry, Schenectady Co., New York		Carapaces abundant; portions of abdomen fragmentary; preservation poor
				Duanesburg and Rotterdam Junction, Schoharie Co., New York		A few carapaces
87. H. shawangunk		Black shales in Shawangunk grit	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Otisville, New York		Very abundant; most nepionic forms
				Delaware Water Gap, Pennsylvania		Several macerated carapaces; one segment showing sculpture
		Olive shales in Tuscarora sandstone		Swatora Gap, Pennsylvania		Several small carapaces
88. H. socialis		Pittsford shale		Pittsford, Monroe Co., New York		Very abundant; entire individuals rather rare
89. H. socialis var. robusta		Pittsford shale		Pittsford, Monroe Co., New York		One nearly entire abdomen; two somites; an imperfect metastoma
90. H. cf. socialis		Keefer sandstone, base of Salina		Pennsylvania—Maryland border		Numerous fragments badly crushed, difficult of indentification
91. Megalograptus welchi		Liberty limestone, middle Richmond		Near Clarkesville, Clinton Co., Ohio		Two fragmentary endognaths, one postabdominal somite
92. Strabops thacheri		Potosi limestone		Flat River, St. François Co., Missouri		One nearly perfect specimen
93. Pterygotus anglicus	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Tealing beds, Pterygotus beds of Carmylie, Acanthodian beds of Turin Hill, the Arbroath flags etc. all of the Caledonian Old Red Sandstone series		Babruddy, Pertshire; Leysmill near Arbroath, Turin Hills, near Reswallie, Tealing and Carmylie, and elsewhere in Forfarshire, Scotland	${\displaystyle \left.{\begin{aligned}\\\\\\\end{aligned}}\right\}}$	Many nearly complete individuals and numerous disjecta membra
94. P. arcuatus		Lower Ludlow		Leintwardine, Shropshire, England		A body segment, two endognaths and some fragments
95. P. atlanticus		Dalhousie limestone (Campbellton beds)		Cempbellton, New Brunswick		Three specimens: a free chela, coxa of a swimming leg, and a small portion of a metastoma
96. P. australis		Upper Siluric flags (Victorian series)		Melbourne, Australia		Four fragments
97. P. barrandei	${\displaystyle \left\{{\begin{aligned}\\\end{aligned}}\right.}$	Ee1 β Kuchelbader graptolite shales		Podol Dvorce, near Prague, Bohemia		A few fragments
		Ee1 β Budňaner limestone		Podol Dvorce, Dlouhá hora, Bohemia
98. P. beraunensis		Ee1 β Kuchelbader graptolite sh.		Podol Dvorce, near Prague, Bohemia		A few endognaths only

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99. P. bilobus var. acidens	${\displaystyle \left.{\begin{aligned}\\\\\\\\\\\end{aligned}}\right\}}$	Divisions 3 and 4 (Peach and Horne) i.e. the Ceratiocaris and Pterygotus beds of the Ludlow	${\displaystyle \left.{\begin{aligned}\\\\\end{aligned}}\right\}}$	Lesmahagow, Lanarkshire, Scotland	${\displaystyle \left\{{\begin{aligned}\\\\\\\\\\\end{aligned}}\right.}$	One antenna, one cephalon, and nearly all the segments of one individual
100. P. bilobus var. crassus						At least one perfect specimen
101. P. bilobus var. inornatus						Many perfect fragments all altered by pressure
102. P. bilobus var. perornatus						An almost entire individual and several incomplete carapaces
103. P. blahai		Ee2 Budňaner limestone		Visňovka near Lochkov, Bohemia		Broken fragments of swimming foot
104. P. bohemicus	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Ee1 β Kuchelbader graptolite shales		Dvorec		Fragments only
		Ee2 Budňaner limestone		Near Budnian, below Karlstein; Dlouhá hora near Karlstein Bohemia		Fragments only
105. P. aff. bohemicus		Ff1 Lochkover limestone		Černá rokle near Kosor, Bohemia		A single claw and part of an abdomen
106. P. buffaloensis		Bertie waterlime		Buffalo, New York		A few nearly perfect individuals and several fragments
107. P. cobbi		Bertie waterlime		Near Buffalo, New York		Two rami of the chelate appendage
108. P. cobbi var. juvenis		Bertie waterlime		Schorley's Farm, Litchfield, Herkimer Co., New York		Two nearly entire specimens
109. P. fissus		Ee2 Budňaner limestone		Dlouhá hora, near Karlstein, Bohemia		A single claw
110. P. gigas	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Downton Castle sandstones		Kington Herefordshire		Fragments numerous
		Downton Castle sandstones (massive sandstone bed)		Ludlow district, Herefordshire and and Shropshire, England		Fragments rare
		Olive shales and Temeside Bone-Bed in Temeside group		Ludlow district, Herefordshire and Shropshire, England		Fragments common
111. P. kopaninensis		Ee2 Budňaner limestone		Near Kopanina, Bohemia		Rare and incomplete fragments
112. P. ludensis	${\displaystyle \left\{{\begin{aligned}\\\\\\\\\\\end{aligned}}\right.}$	Downton Castle sandstones		Ludlow district Herefordshire and Shropshire, England		Fragments rare
		Olive shales and Temeside Bone-Bed, Temeside group		Ludlow district, Herefordshire and Shropshire, England		Fragments common
		Transition beds to Old Red		Trimpley, near Kidderminster, Herefordshire, England		One specimen with nearly all of body somites and telson; a few other fragments
113. P. macrophthalmus		Bertie waterlime		Williamsville, Erie Co.; Litchfield, Herkimer Co.; Waterville, Oneida Co., New York		Three nearly perfect specimens and a few fragments

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species		horizon and facies	locality		condition
114. P. minor		Indurated shale overlying Arbroath flags	Farnell, Forfarshire, Scotland		One small almost perfect specimen
115. P. monroensis		Pittsford shale	Pittsford, Monroe Co., New York		One cephalothoracic shield
116. P. (Eusarcus?) nasutus	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Normanskill shale	Broom Street Quarry, Catskill, New York		Several carapaces
		Schenectady shale	Schenectady, Aqueduct, and Duanesburg, Schenectady Co., New York		Several carapaces
117. P. nobilis	${\displaystyle \left\{{\begin{aligned}\\\end{aligned}}\right.}$	Ee1 β Kuchelbader graptolite shales	Podol Dvorce, Bohemia	${\displaystyle \left.{\begin{aligned}\\\end{aligned}}\right\}}$	Fragments only
		Ee2 Budňaner limestone	Near Kolednik, Bohemia
118. P. normanskillensis		Normanskill shale	Broom Street Quarry, Catskill, New York		Carapces; possibly some telsons
119. P. problematicus	${\displaystyle \left\{{\begin{aligned}\\\\\\\\\\\\\end{aligned}}\right.}$	May Hill sandstone	Abelish, Eastnor Park, near Ledbury, Herefordshire		Chela only
		Throughout entire Upper Ludlow group	At Whitcliff and many localities in and near Ludlow, Herefordshire		Fragments rare
		Platyschisma beds, Temeside group	Ludlow district	${\displaystyle \left.{\begin{aligned}\\\\\\\end{aligned}}\right\}}$	Fragments abundant, but poorly preserved. No entire individuals
		Downton Castle sandstones, Temeside group	Bradnor Hill, Kington, and near Ludlow, Herefordshire
		Olive shales, Upper Temeside group	Ludlow district
		Temeside Bone-Bed	Ludlow district
120. P. cf. problematicus Salter (Semper)		Ee2 Budňaner limestone	Kolednik Bohemia		A single fragment of a chela
121. P. prolificus		Schenectady shales	Schenectady, Aqueduct, Rotterdam Junction, Duanesburg, Schoharie Junction, Uly Crreek, New York		A number of fairly complete carapaces
122. P. ? stylops		Downton Castle sandstones	Kington, Herefordshire, England		Anterior portion of a single carapace
123. P. taurinus		Ledbury shales	Ewyas Harold, Herefordshire		A nearly complete carapace, portions of telson and body segment, and fragments
124. P. sp. Siemiradzki		Devonic limestone	Skala, Podolia		A single telson

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125. P. sp. H. Woodw.		Knoydart formation		McArras Brook, Antigonish Co., Nova Scotia		Specifially indeterminable fragments
126. P. (Erettopterus) banksii	${\displaystyle \left\{{\begin{aligned}\\\\\\\\\end{aligned}}\right.}$	Ludlow Bone-Bed		Ludlow	${\displaystyle \left.{\begin{aligned}\\\\\\\\\end{aligned}}\right\}}$	Many specimens, none complete; fragments abundant
		Platyschisma-beds in Temeside group		Ludlow
		Downton Castle sandstones		Ludlow Lane, Whitcliffe, Parlan, exterior slope of Woolhope Valley, Kington, Herefordshire
		Olive shales, Upper Temeside group		Ludlow England
127. P. (Erettopterus) globiceps	${\displaystyle \left\{{\begin{aligned}\\\end{aligned}}\right.}$	Shales in the Shawangunk grit Shales in Tuscarora sandstone	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Otisville, New York	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	No entire specimens; several carapaces, a few body segments, a swimming leg several telsons; four immature individuals
				Swatora Gap, Pa		Several small carapaces
128. P. (Erettopterus) cf. globiceps		Shales in the Shawangunk grit		Delaware Water Gap, Pennsylvania		A small distorted carapace
129. P. (Erettopterus) grandis		Bertie waterlime		Buffalo, New York		A single telson
130. P. (Erettopterus) osiliensis	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Zone K, Eurypterus waterlimes of Oesel		Rotziküll, Oesel		Many seperated members; no entire individuals
		Pterygotus marl		Visby, Gotland		Fragmentary, but abundant
		Transition beds to Devonic of Galicia		Zalesczyki, Galicia		Fragments, determined with difficulty
131. Slimonia acuminata		Div. 3, 4, 5 & 6 (Peach and Horne), Ludlow		Banks of Logan Water, Lesmahagow, Lanarkshire		One nearly perfect specimen; dismembered organs abundant
132. S. cf. acuminata (Seemann)		Ee2 Budňaner limestone		Dlouhá hora, Bohemia		One fragment of an ectognath
133. S. dubia		Wenlock shale and sandstone		Gutterford Burn, Pentland Hills, Edinburgshire, Scotland		Badly preserved carapace and parts of first eleven somites
134. Stylonurus beecheri		Chemung sandstones		Warren, Warren Co., Pennsylvania		One incomplete individual
135. S. ensiformis		Turin beds, Caledonian Old Red Sandstone		Turin Hill Quarries, near Reswallie, Forfarshire		A single incomplete telson
136. S. ? limbatus		Schenectady shale		Schenectady and Duanesburg, Schenectady Co., New York		Six carapaces, two doubtfully identified
137. S. logani		Pterygotus beds, div 4 (Peach and Horne)		Logan Water, Lesmahagow, Lanarkshire		One incomplete specimen, showing carapace, ten body segments and a few appendages
138. S. macrophthalmus		Wenlock shales and sandstones		Gutterford Burn, Pentland Hills, Edinburgshire, Scotland		One complete individual; several fragments

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species		horizon and facies		locality	condition
139. S. megaolps		Olive shales, Temeside group		Ludlow railroad cut, Herefordshire	Fragments common, carapaces especially, but all broken
140. S. modestus		Normanskill shale		Broom Street Quarry, Catskill, New York	Several small carapaces, portions of the abdomen, a leg
141. S. myops		Shales in the Shawangunk grit	${\displaystyle \left\{{\begin{aligned}\\\\\end{aligned}}\right.}$	Otisville, New York	One entire individual poorly preserved; numerous carapaces; some with attached somites
				Delaware Water Gap, Pennsylvania	Several large and small carapaces
142. S. ornatus		Wenlock shales and sandstones		Gutterford Burn, Pentland Hills, Scotland	Three or four fragments including portions of carapace, abdomen, appendage and telson
143. S. powriei		Turin beds, Caldeonian Old Red Sandstone		Turin Hills, near Pitscandly, Forfarshire, Scotland	One nearly complete individual
144. S. symondsii		Cornstones middle Old Red		Rowlestone, south of Hay, Brecknockshire, England	One well preserved carapace
145. S. (?) scabrosus	${\displaystyle \left\{{\begin{aligned}\\\\\\\end{aligned}}\right.}$	Calciferous shales		Glencartholm, Eskdale, Scotland	One incomplete specimen, showing cephalon, portions of first 10 somites and fragments of appendages
		Lower Carbonic shales and clay iron stones		Sedgley, near Dudley, Staffordshire, England	One incomplete individual with some of the appendages attached
146. S. ? wrightianus		Portage sandstones		Italy, Yates Co., New York	A single, twp-jointed fragment; may be part of appendage
147. S. (Ctenopterus) cestrotus		Shales in Shawangunk grit		Otisville, New York	Rare form; a few nearly complete individuals; a few carapaces
148. S. (Ctenopterus) elegans		Wenlock shales and sandstones		Gutterford Burn, Pentland Hills, Scotland	Five fragmentary specimens certainly, two more probably
149. S. (Ctenopterus) excelsior		Catskill sandstones	${\displaystyle \left\{{\begin{aligned}\\\end{aligned}}\right.}$	Andes, Delaware Co., New York	External mold of complete carapace
				Wyoming Co., New York	Fragmentary carapace
150. S. (Ctenopterus) multispinosus		Pittsford black shale		Pittsford, Monroe Co., New York	Six incomplete endognathites and one somite

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151. S. (Drepanopterus) bembicoides	Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Scotland	Two incomplete specimens
152. S. (Drepanopterus) lobatus	Wenlock shales and sandstones	Gutterford Burn, Pentland Hills, Scotland	One nearly complete individual, two or three fragments
153. S. (Drepanopterus) longicaudatus	Kokomo waterlime	Kokomo, Indiana	Form not described
154. S. (Drepanopterus) pentlandicus	Wenlock shales and sandstones	Gutterford Burn, Pentland Hills	Several nearly perfect and two fragmentary individuals
155. S. (Tarsopterus) scoticus	Caldeonian Old Red Sandstone	Montroman Muir, near the Forfar and Montrose Pike, Forfarshire	One carapace and an almost entire individual
156. S. sp. α Clarke and Ruedemann	Shales in Shawangunk grit	Otisville, New York	Two fragments of leg joints of uncertain specific relations
157. S. sp. β Clarke and Ruedemann	Shales in Shawangunk grit	Otisville, New York	Terminal joints of leg
158. S. sp. γ Clarke and Ruedemann	Shales in Shawangunk grit	Otisville, New York	Fragments of segment and of integument
159. S. sp. δ Clarke and Ruedemann	Shales in Shawangunk grit	Otisville, New York

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In order to facilitate the use of the preceding tables, I shall give here a synonymy which is not complete, but is intended only for the convenience of anyone looking for a species which has been revised, and which would not appear under the genus to which it was originally ascribed. Such a synonymy is particularly necessary for species described in foreign literature. Most of the revisions have been made by Clarke and Ruedemann for American and some European species, by H. Woodward for species in Great Britain, by Semper for those in Bohemia originally described by Barrande, and by numerous other writers who have revised only single species.

Original Name	Present Name or Status
Adelopthalmus granosus Jordan	Eurypterus (Adelopthalmus) granosus (Jordan)
Carcinosoma newlini Claypole	Eusarcus newlini (Claypole)
C. ingens Claypole	Eusarcus newlini (Claypole)
Ceratiocaris grandis Pohlman	Pterygotus (Erettopterus) grandis (Pohlman)
Dolichocephala lacoana Claypole	Stylonurus (Ctenopterus) excelsior Hall
D. macrocheirus Hall	Dolichopterus macrochirus Hall
D. mansfieldi C. E. Hall	Eurypterus (Anthraconectes) mansfieldi (C. E. Hall)
Drepanopterus bembycoldes Laurie	Drepanopterus bembicoides Laurie
D. bembicoides Laurie	Stylonurus (Drepanopterus) bembicoides (Laurie)
D. lobatus Laurie	Stylonurus (Drepanopterus) lobatus (Laurie)
D. longicaudatus Clarke and Reudemann	Stylonurus (Drepanopterus) longicaudatus (Laurie)
D. pentlandicus Laurie	Stylonurus (Drepanopterus) pentlandicus (Laurie)
Echinocaris wrightiana Jones and Woodward	Stylonurus (?) wrightianus (Dawson)
E. wrightiana Etheridge, Woodward and Jones	Stylonurus (?) wrightianus (Dawson)
Eurypterus acrocephalus Semper	Eusarcus acrocephalus (Semper)
E. beecheri Hall	Stylonurus beecheri (Hall)
E. beecheri Hall and Clarke	Stylonurus beecheri (Hall)
E. chartarius Salter	Eurypterus lanceolatus Salter
E. ? cicerops Clarke	Eusarcus (?) cicerops Clarke
E. eriensis Whitfield	Eurypterus microphthalmus Hall
E. giganteus Pohlman	Eurypterus pustulosus Hall
E. lacustris Hibbert	Eurypterus lacustris Harlan
E. lacustris Hall var pachychirus Hall	Eurypterus pachychirus Hall
E. laticeps Schmidt	Dolichopterus laticeps (Schmidt)

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Original Name	Present Name or Status
E. mansfieldi James Hall	Eurypterus (Anthraconectes) mansfieldi (C. E. Hall)
E. (Arthropleura) mammatus Salter	Not a eurypterid
E. maria (in part) Clarke	Pterygotus (Erettopterus) globiceps Clarke and Ruedemann
E. megalops Clarke and Ruedemann	E. ruedemanni O'Connell
E. megalops Salter	Stylonurus megalops (Salter)
E. pennsylvanicus James Hall	Eurypterus (Anthraconectes) pennsylvanicus C. E. Hall
E. obesus H. Woodward	Eusarcus obesus (H. Woodward)
E. myops Clarke	Stylonurus myops Clarke
Cf. E. potens James Hall	Eurypterus
E. pugio Barrande	Doubtful determination, no standing
E. punctatus H. Woodward	Eusarcus punctatus (Salt.)
E. punctatus Salter	Eusarcus punctatus (Salt.)
E. aff. punctatus Woodw. et acrocephalus Semper	Eusarcus punctatus (Salt.)
E. remipes Logan	Eurypterus lacustris Harlan
E. remipes Bronn and Roemer	Eurypterus lacustris Harlan
E. scoticus Laurie	Eusarcus scoticus (Laurie)
E. scouleri (?) Salter	Eurypterus hibernicus (Baily)
E. simonsoni Schmidt	Eusarcus simonsoni (Schmidt)
E. scorpioides H. Woodw.	Eusarcus scorpioides (H. Woodw.)
E. stylus James Hall	Eurypterus (Anthraconectes) mansfieldi (C. E. Hall)
E. symondsii Salter	Stylonurus symondsii (Salter)
E. tetragonophthalmus Fischer	Eurypterus fischeri Eichwald
Eurysoma newlini Claypole	Eusarcus newlini (Claypole)
Eusarcus grandis Grote and Pitt	Eusarcus scorpionis Grote and Pitt
E. scorpionis Pohlman 1881	Eusarcus scorpionis G & P not E. scorpionis Pohlman 1886
E. scorpionis Semper	Eusarcus scorpionis G & P
E. scorpionis Seeman	Eusarcus scorpionis G & P
Equisetides wrightiana Dawson	Stylonurus (?) wrightianus (Dawson)
E. wrightiana Wright	Stylonurus (?) wrightianus (Dawson)
Himantoperusa cuminatus Salter	Slimonia acuminata (Salter)
H. acuminatus D. Page	Slimonia acuminata (Salter)
H. bilobus Salter	Pterygotus bilobus var. inornatus (Salter)
H. banksii Salter	Pterygotus (Erettopterus) banksii (Salter)
H. lanceolatus Salter	Eurypterus lanceolatus (Salter)
H. maximus Salter	Slimonia acuminata (Salter)
H. perornatus Salter	Pterygotus bilobus var. perornatus Woodw.
Pterygotus acuminatus Salter	Slimonia acuminata (Salter)

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Original Name	Present Name or Status
P. acuticaudatus Pohlman	Pterygotus buffaloensis (Pohlman)
P. banksii Salter	P. (Erettopterus) banksii Salter
P. buffaloensis Pohlman	P. buffaloensis (Pohlman)
P. cobbi (P. cummingsi) Semper	P. cobbi Hall
P. comes Barrande	P. bohemicus Barrande
? P. cummingsi Grote and Pitt	P. buffaloensis (Pohlman)
P. cummingsi Grote and Pitt	P. cobbi Hall
P. cyrtochela Barrande	Doubtfully identified, no standing
P. expectatus Barrande	Doubtfully identified, no standing
P. globicaudatus Pohlman	Eurypterus pustulosus Hall
P. globicaudatus Laurie	Eurypterus pustulosus Hall
P. hibernicus Baily	Eurypterus hibernicus (Baily)
P. macrophthalmus ? Pohlman	P. buffaloensis (Pohlman)
P. mediocris Barrande	Doubtfully identified, no standing
P. osborni Hall	Pterygotus macrophthalmus Hall
P. perornatus Salter	P. bilobus var. perornatus Woodw.
P. perornatus var. plicatissimus	P. bilobus var. perornatus Woodw.
P. problematicus Agassiz	P. problematicus Salter
P. problematicus Banks	P. gigas Salter
P. problematicus Strickland and Salter	P. problematicus Salter
P. punctatus Salter	Eusarcus punctatus (Salter)
P. pugio Barrande	Doubtfully identified, no standing
P. quadricaudatus Pohlman	Pterygotus buffaloensis (Pohlman)
P. raniceps (Woodw.)	Eusarcus raniceps (Woodw.)
P. sp. Whiteaves	P. atlanticus Clarke and Ruedemann
? P. sp. Sarle	P. monroensis Sarle