the party ; and they are inserted simply to illustrate certain parts of the context, 

 which would be unsatisfactory without reference to figures of the kind. 



Now that the present work is ready for the press, we are very sensible that 

 it must contain errors which, while they have escaped our notice, will be readily 

 detected by eyes more experienced. These, we trust, will be excused, when 

 it is remembered that we are just entering a field which others have explored 

 for years ; and opening a work which Princeton, with her many other lines 

 of study, has never hitherto attempted. 



We take this opportunity to return our most hearty thanks to General 

 Flint, to Judge and Dr. Carter, to Mr. Hamilton, and other officers and 

 residents at Fort Bridger, who, by their good will and liberal assistance, con- 

 tributed largely to our success. Our gratitude is also due to Professors Leidy 

 and Cope for their generous aid, both in the way of advice and of material 

 put in our hands for comparison. 



The following pages do not embrace descriptions of the entire collections 

 made by the Princeton party last summer. The valuable specimens of fossil 

 plants and insects have passed into other hands. 



Respectfully submitted, 



HENRY F. OSBORN, 

 WM. B. SCOTT, 



FRANCIS SPEIR, JR. 

 Dr. ARNOLD GUYOT, 



Director of the E. M. Museum. 



