PREFACE. 



The question of the origin of land vertebrates, which has appealed so strongly 

 to students of fossil Amphibia, is by no means solved from the material furnished 

 by the Coal Measures of North America. The Amphibia are, however, well known 

 from several localities in the Coal Measures of this continent, where skeletons have 

 been recovered which are sufficiently well preserved to afford a fair knowledge of 

 their anatomy. The specimens rescued from the dumps of the coal mines are regret- 

 tably few in comparison with the number that must have been burned as fuel, or 

 carried down the slopes as silt. Yet scanty as is the material thus collected, it is of 

 great importance, because it represents such an early period in the recorded history 

 of the air-breathing vertebrates. 



The amphibian fauna in the Coal Measures of North America is represented by 

 several hundred individual specimens, preserved in various museums. All of the 

 collections have been available in the preparation of this memoir, with the exception 

 of those species from Nova Scotia which are preserved in the Peter Redpath 

 Museum of McGill University and in the British Museum of Natural History. The 

 European material, which has been used in comparisons with the American forms, 

 has been studied chiefly from the literature, although there have been available a 

 series of specimens of Branchiosaurus amblystomus Credner, from Saxony, presented 

 by the late Professor Credner, and a single specimen of Archegosaurus from Dr. von 

 Huene, of Tubingen. 



The collection which has been of the greatest value is that at the American 

 Museum of Natural History, chiefly assembled by Dr. J. S. Newberry from the 

 dumps of the coal mines at Linton, Ohio, while he was in charge of the Ohio Geo- 

 logical Survey (1869-1884). This collection, a part of which is at Columbia Uni- 

 versity, furnished Cope with the most of his type material for the "Synopsis of 

 the Extinct Batrachia from the Coal Measures" (123).* This entire collection, 

 including all of Professor Cope's types and representing many new and hitherto 

 undescribed forms, was generously placed at the writer's disposal for a period of 

 five years through the kindness of Dr. Bashford Dean and Dr. Louis Hussakof . Dr. 

 Hussakof made a trip through the Linton region and his description of the place 

 occupied by the "Old Diamond Mine" is given on page 16. 



An interesting collection of air-breathing vertebrates from the Coal Measures, 

 representing 19 species, is in the U. S. National Museum (464). This is chiefly the 

 collection of Mr. R. D. Lacoe and includes specimens from Mazon Creek, Illinois, 

 from Kansas, and from Linton, Ohio. It is especially important in that it contains 

 the skeleton (plate 20, fig. 3) of the oldest known reptile, Eosaurnvns copei Williston 

 (Jour. Geol., xvi, 295). It contains also, besides many of Cope's types, new forms 

 which have been described by the writer (464, 470, 471, 472, 473, 474, 478, 47^). 

 Dr. Stuart Weller first secured the use of this collection for me, and its continued use 

 has been granted by Dr. C. D. Walcott. Mr. Charles Gilmore has called my atten- 

 tion to several interesting specimens and has kindly loaned them for description. 



The numbers in parentheses refer to the bibliography at the end of this volume. 



v 



