PRINCETON, June i, 1878. 



SIR : We transmit herewith our report upon the Palaeontological collec- 

 tions made by the Princeton party in the summer of 1877. 



The following persons constituted the Palaeontological division : ROLLIN H. 

 LYNDE, HENRY F. OSBORN, JOTHAM POTTER, WM. B. SCOTT, FRANCIS SPEIR, Jr. 

 The division remained in Colorado from the first of July until the first of 

 August, when, under the direction of Professor Karge, it left the main party, 

 and passed the month of August in Wyoming, returning in the first part of 

 September. The Colorado collections were mostly made in the (probable) 

 Miocene beds near Florissant, and in the beds near the Garden of the Gods, 

 variously referred to the Dakota and IVealden groups. In Wyoming, with 

 Fort Bridger as a base of explorations, the division was wholly occupied in 

 the Bridger series, camping successively on Smith's Fork, Henry's Fork, and 

 Dry Creek, and exploring the beds adjacent. 



It has been our endeavor, in confining our attention to the remains of 

 vertebrated animals collected during the trip, not merely to catalogue the direct 

 results, but, by the aid of fresh materials, to supplement the work of others. 

 For, of the descriptions and data of the Bridger Eocene Fauna published up 

 to the present time, we find that even those which have been most accurately 

 prepared are lacking in important details ; and that, owing to imperfect mate- 

 rials, large gaps yet remain in our knowledge of genera and species named 

 and classed years ago. Although such supplementary work may appear, at first 

 sight, tedious and ill-directed, we are confident that in the end it will prove of 

 some value to science, and that it is therefore well worthy of our effort. While 

 our field work did not extend beyond a region previously well explored, we 

 obtained material by means of which we are able to add a number of new 

 ossils to the Eocene Fauna of the Bridger group. 



In the preparation of this report we have experienced much difficulty in 

 assigning some of our specimens to their proper genera and species. For, 

 while we have desired to respect the classifications made by others, we have 

 in many cases found it impossible to do so, owing to uncharacteristic definition, 

 which, without doubt, has been unavoidable. In all cases of uncertainty, we 

 have adopted the classification which appeared to be the best established. 

 This, in short, has proved the only available course. 



The drawings have been executed with much care as to accuracy o/ pro- 

 portion and outline. They are, with one exception, the work of a member of 



