The Eurypterida of New York/Volume 1/Preface

by John Mason Clarke and Rudolf Ruedemann

PREFACE

While the senior author of this work was engaged in the preparation of the monograph of the American Devonic Crustacea which constituted volume 7 of the Palaeontology of New York [1888], the forms of the Eurypterida there presented for consideration, led to the impression that it would be a service to paleontology to restate in detail the structure of this unique group of extinct creatures. The Siluric rocks of New York had proven so profuse in these remains that the material was not wanting for such analysis; the late Professor James Hall, who in 1859 had given the most intimate account of the eurypterids developed up to that time, concurred in the belief that the 30 years which had then passed would, with the aid of accumulated data and in the light of the contributions made by other writers, afford new facts worth recording. Not long after this Gerhard Holm published his very remarkable analysis of the structure of Eurypterus based on specimens from the Baltic Siluric and on the appearance of this exhaustive memoir it seemed that the anatomy of the group could hardly be supplemented except by the estimation of specific and generic differences, and the study of the habitudes of these animals. Notwithstanding, as early as 1895, I began the assemblage of materials looking specially to a revision of the New York and American eurypterid faunas. The collections of the State Museum were already pretty well supplied with representatives from the well known localities at Buffalo and in Herkimer county and now these collections have been vastly amplified, first by repeated acquisitions from the Herkimer county localities during the past 15 years, again by the close study of all outcrops of the Eurypterus beds along the line between Herkimer county and Buffalo which has progressed in connection with the field work in areal geology, then by the courtesy of the trustees of the Buffalo Society of Natural Sciences who in 1898, by special vote, placed at my disposal the extraordinary assemblage of specimens from the Buffalo cement quarries which is known, from the name of its principal contributor, as the Lewis J. Bennett Collection. Soon thereafter followed the discovery of the Eurypterus-bearing black shales at Pittsford, Monroe co., which were brought to light by the work of enlargement of the Erie canal in 1895, the species of which were described in our reports by Mr Clifton J. Sarle from material now in possession of the State Museum. To this notable addition to our knowledge has been added in years still more recent the new fauna in the dark shales of the Shawangunk grit at Otisville, Orange co., an assemblage of eurypterids remarkable for its profusion of immature growth stages; this fauna lying far to the east of all previously known occurrences of these creatures, was described in a preliminary way by the writer. Still more recently, indeed since the preparation of this book was believed to be completed, the field investigations of Dr Ruedemann have brought to light a large and new fauna in the Lower Siluric (Frankfort) shale rather widely disseminated in the lower Mohawk valley and this constitutes the very earliest assemblage of these merostomes in conditions which indicate that they formed a colony of long local duration.

The collections which have thus been brought together from the productive localities mentioned for the preparation of the present treatise have been really great; indeed they represent some thousands of specimens and it is quite within reason to say that no series of the Eurypterida of equal size and variety has ever before been assembled. It is quite as true that no equal area in the world has proved as fruitful in the quantity and diversity of these organisms as the State of New York. And through the courtesy of many correspondents and museums much material from outside of New York has been placed at the demands of this work: the species of the Kokomo waterlimes of Indiana; of the Cambric Strabops of Missouri; the Siluric Megalograptus of Ohio and the Carbonic Hastimima of Brazil and New Brunswick; in all, I believe, an unexampled array of these extinct arachnids.

The work of elaborating these earlier studies and expanding them into this fuller form has very largely depended on the aid of Dr Rudolf Ruedemann who has brought to the work keen analytical powers, a broad grasp of its problems and an enthusiastic assiduity. I fully realize and gladly express my obligation to this assistance and desire that the interested reader accord to my coworker adequate acknowledgment of his efficient part in this work.

The treatise itself seems to carry its own justification; aside from the close analysis of structural details, there are chapters on ontogeny, phylogeny, on life habits and conditions as well as on organization which, though probably not beyond criticism, are at least informing and constitute an advance of knowledge.

To the following individuals and institutions the authors have been indebted for aid:

The Buffalo Society of Natural Sciences, through its board of trustees and its superintendent, Mr Henry R. Howland

The American Museum of Natural History, through Dr E. O. Hovey and the late Prof. R. P. Whitfield

The United States National Museum, through Drs R. S. Bassler, E. O. Ulrich and David White

The Smithsonian Institution, through Secretary Charles D. Walcott

Columbia University, through Profs. A. W. Grabau and Jesse E. Hyde

Museum of Comparative Zoology, Cambridge, through Dr Samuel Henshaw

The Peter Redpath Museum, McGill University, through Dr Frank D. Adams

Geological Survey of Canada, through Dr Percy E. Raymond

Dr E. M. Kindle, Washington

Prof. Stuart Weller, Chicago

Prof. Gilbert van Ingen, Princeton

Dr Mark E. Reed, Buffalo

Mr Irving P. Bishop, Buffalo

Dr August F. Foerste, Dayton, Ohio

Mr Fred Braun, Brooklyn

The illustrations in the work are from drawings skilfully rendered by George S. Barkentin, many of them, especially the restorations and stages of immature growth, based on Dr Ruedemann's sketches and camera drawings.

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The eurypterid colonies of the New York Siluric are very distinctly localized and of them we know two at the bottom of the Salina series or beneath the salt beds and two at the top of the series. These colonies were doubtless in part breeding pools in brackish waters, partly more open basins, restricted in extent by the limitations of favorable physical conditions.

Colony O, or the Otisville basin lying far eastward of the rest and on the borders of the Appalachian region, is embedded in an almost unlimited repetition of thin black shale between layers of heavy sandstone of the Shawangunk formation (Salina stage). In the construction of railroad improvements the rock wall here was broken down for ballast and while this work was in progress the eurypterid remains were detected by Dr Ruedemann. From this time on until the completion of the construction work referred to, Mr H. C. Wardell was almost continuously engaged in acquiring these fossils and when the work was done the rock exposure was left with a vertical face, so that no further product is now available. In this eastern region of New York State the Salina formation is without salt deposits but the Otisville basin doubtless antedated those deposits in central New York and is assignable to an early part of the Salina stage.

Colony P, or the Pittsford pool, is embedded in a black shale formation which has never been exposed in any natural outcrops. As we have observed, the rock was first brought to light by excavations made in the deepening of the Erie canal in 1895 and the outcrops were soon after covered by the riprap construction of the canal lining and so remain. Extensive collections of material were made by Mr Clifton Sarle and these were subsequently increased by the work of Messrs D. D. Luther, H. C. Wardell and Fred. Braun. The opportunity of further acquisitions from this fauna rests with the future and depends on possible new excavations in the progress of public improvements.

Colony H, or the Herkimer pool, has been long exploited. It lies above the horizon of the salt and its localities are in the vicinity of Jerusalem Hill, Clayville, Sauquoit and Waterville. The most productive parts of the region have been the Wheelock and Schooley farms near Jerusalem Hill, though here as elsewhere actual outcrops of the waterlime are few. Experience has shown that the exploitation of the fresh rock does not afford eurypterids in satisfactory preservation, because of its blue gray character. Exposure not only reduces this to a light gray but aids the fissility of the rock and the broad, flat surfaces of the fossils also help to induce cleavage planes in the matrix. Exposure of a few years to the weather aids but little. The experiment was made of taking from the outcrop a good many cords of fresh rock which were left exposed for a period of five years but the result in the particulars referred to was wholly unsatisfactory. Therefore the supply of these fossils has come from weathered slabs distributed over this region. Miles of stone fences have been inspected and many rods of them taken down and rebuilt. Some of the most productive material has been found in the foundations and cellar walls of buildings and in one instance the foundation wall of a large barn has been removed without disturbing the building, the abstracted rock being replaced with concrete as the work proceeded. Many hands have helped in the acquisition of this material: Messrs D. D. Luther, R. Ruedemann, C. A. Hartnagel, Jacob Van Deloo, H. C. Warden, Fred Braun and the writer, and while it may be difficult at the present to greatly enlarge these extensive collections, still they are only an index of the profusion of these forms of life in this pool.

Colony B, or the Buffalo pool, appears to have been quite closely confined to the quarry beds of the Buffalo Cement Company in the northern part of the city of Buffalo. It is from these quarries that the majority of the specimens widespread now through the museums of the world, has come. Formerly such specimens were available to any collector, but a few years ago the president of the company determined to place all specimens uncovered in the progress of quarry work in the possession of the Buffalo Society of Natural Sciences and by virtue of this laudable act that society possesses in the "Bennett Collection" a very remarkable array of these remains, which are specially noteworthy for the prevailing large size attained by the individuals. At the present time few Eurypterida are obtained from this historic locality and there is reason to believe that the boundaries of the pool have been approached, though remains of these creatures are found scattered at this geological horizon as far west as Bertie, in Ontario, the locality from which this waterlime formation takes its name. Like the Herkimer pool, that at Buffalo lies in the Bertie waterlime above the salt.

Colony S, or the Schenectady basin. This recent discovery (1910) of eurypterids in the Frankfort shale (Lower Siluric) is comparable to their occurrence at Otisville. These remains, usually in fragmentary condition, abound most freely in fine grained black shale intercalated between thick calcareous sandstone beds locally known as "Schenectady bluestone," but they also occur in the sandy passage beds between the two. These sandy shales are full of organic remains, partly of the supposed seaweed Sphenothallus latifolium Hall and partly of what appear to be large undefined 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 this assemblage, but it is safe to say genera, species and individuals were abundant at this early period, and the evolution of distinctive characters which we have heretofore recognized only in a later period had progressed to so sharp a differentiation, that we are compelled to carry back further in history, some of the commoner generic designations. These remains in the Frankfort shale are distributed through fully 1500 feet of strata deposited off a northeast-southwest coast line in an area of maximum deposition, and it is difficult to conceive that the physical conditions of the habitat of these merostomes were those of an inshore pool—rather those of a purely marine basin where sedimentation went on rapidly in an appalachian depression. Hence this occurrence is without parallel among our assemblages of these creatures in respect to long endurance.

All other occurrences of Siluric eurypterids in New York have been desultory and indicate no intercommunication between the pools or colonies mentioned.

John M. Clarke