PREFACE. 



In this treatise on the Fossil Turtles of North America there are described 

 266 species, of which 76 are regarded as hitherto unknown to science. In the 

 preparation of this work the writer has had access to most of the collections which 

 contain remains of North American fossil turtles. The most important of these 

 collections is that of the American Museum of Natural History, in New York. 

 In this are found many of the specimens described by Professor E. D. Cope, 

 including many of his types. In addition to these, large numbers of turtles have 

 been brought together by the expeditions sent out by this museum during the past 

 fifteen years. Free access has been given the writer to the materials in the United 

 States National Museum, where there are many of the specimens described by 

 Dr. Joseph Leidy and Professor Cope; to those of the Academy of Natural Science 

 of Philadelphia, where are found other materials rendered precious by the labors 

 of the authors just mentioned; to those of the Carnegie Museum, Pittsburgh; 

 the Field Natural History Museum, Chicago; the University of Kansas, Lawrence; 

 the University of Texas, and the University of Nebraska. At Yale University 

 the writer has been permitted to study and describe valuable materials brought 

 together by Professor O. C. Marsh, besides other specimens which form the 

 types of species described more recently by Dr. George R. Wieland. Thru the 

 courtesy of Professor W. S. Valiant some of Dr. Leidy 's types preserved at Rutgers 

 College were made accessible. Specimens for study have been sent to the writer 

 from most of the museums mentioned; also from the University of Chicago, by 

 Mr. S. W. Williston; from the University of California, by Dr. J. C. Merriam; 

 from the Geological Survey of Canada, by Mr. L. M. Lambe; and from the 

 Vanderbilt University, Nashville, by Professor L. C. Glenn. 



It has been the author's earnest wish to see all the types of the hitherto described 

 species; and most of these have come under his notice. Unfortunately some are 

 without doubt utterly lost; others have, for the time, disappeared from view. 



The author has endeavored to illustrate as fully as possible the species described. 

 Whatever mayprove to be the little or great value of the text, the writer can commend 

 the illustrations. By far the greater number of the figures of the plates are from 

 photographs which were taken at the American Museum of Natural History by 

 Mr. A. E. Anderson. Other photographs and drawings have been furnished by 

 the Geological Survey of Canada thru Mr. L. M. Lambe; others by Dr. George R. 

 Wieland, of the Yale University Museum; others by Dr. W. J. Holland, director 

 of the Carnegie Museum, Pittsburgh. The photographs of Basilemys sinuosa 

 came from the Field Natural History Museum, thru Dr. E. R. Riggs. A consider- 

 able number of the drawings found in the plates were prepared many years ago, 

 for the late Dr. George Baur, by the United States Geological Survey; thru the 

 courtesy of the Survey these were placed in the hands of the writer. The major- 

 ity of the drawings that appear in the text were executed by Mrs. Lindsay Mor- 

 ris Sterling, artist in the department of vertebrate paleontology in the American 

 Museum of Natural History. A number of these text-figures are the work of Mr. 



