14 INTRODUCTION. 



sonian Institution, visited the locality in 1850, and brought home a valuable addi- 

 tional collection of mammalian and chelonian fossils. 



From a variety of favorable circumstances, but especially through important aid 

 from the Smithsonian Institution, and Dr. D. D. Owen, I have been enabled per- 

 sonally to inspect all the animal remains brought from Nebraska, of vrhich I have 

 had any intimation. In commencing, then' with a description of the Eocene Fauna 

 of Nebraska, the following collections were submitted to investigation. 



1. The original fragment of a maxillary bone described by Dr. Prout, Avith the 

 addition of several other important specimens. These were kindly loaned by Dr. 

 Hiram A. Prout, of St. Louis. 



2. A collection which accompanied the former, belonging to, and obligingly 

 loaned by Prof. O'Loghland, of St. Louis. 



3. Specimens presented by Alexander Culbertson, Esq., through Joseph Cul- 

 bertson, Esq., to the Academy of Natural Sciences, of Philadelphia. 



4. The collection made by Dr. John Evans, at the instigation of Dr. D. D. 

 Owen, for the United States Government, and now belonging to the Smithsonian 

 Institution. 



5. A collection procured, as above mentioned, by Mr. Thaddeus A. Culbertson, 

 for the Smithsonian Institution. Very important aid in making this collection was 

 rendered by Mr. Alexander Culbertson. 



6. A small but very excellent collection made by Captain Stewart Van Vliet, of 

 the United States Army, and by him presented to the Smithsonian Institution. 

 These specimens, though last received, were actually among the first collected, 

 having been procured by him when on a journey from Fort Pierre to Fort Lara- 

 mie, in company with Mr. Alexander Culbertson, who, on the same occasion, ob- 

 tained the specimens first described by me. 



Most of the specimens when received, were partially enveloped by, or had 

 attached to them a hard, silicio-calcareous clay, of a dirty cream color; and the 

 same material fills the cavities of the skulls and the interior of the turtle shells. 



This matrix, according to Dr. D. D, Owen, has the following composition : — * 



Water of absorption ......... HO 2.50 



Flesh-colored silicious earth, insoluble in ehlorohydric acid . . 33.00 



Lime CaO 30.90 



Carbonic acid CO^ 19.00 



Sesquioxide of iron ......... FcjOj 2.00 



Alumina AlA 1.00 



Manganese MnO 1.00 



Magnesia MgO 1.00 



Phosphoric acid ......... 1.80 



Chlorine CI 0.44 



Potash KO 4.08 



Soda and loss NaO 3.28 



100.00 



' Rep. of a Geolog. Surv. etc., p. 606. 



