GENERAL OBSERVATIONS. 75 



large reptile in Jurassic strata of Northwestern Colorado. The collection of 

 Mr. Cleburn also contains two or three species of insects. 



The study of the collections as a whole, reveals many interesting- facts 

 bearing upon the physical conditions of the regions examined, during the 

 deposition of the strata from which they have been collected, some of which 

 are briefly discussed on following pages. Among the more important of 

 these is the identification of the marine genera Oculina^Phorus, Dentalium, 

 Patella, Venus, Mesodesma, c., from the Tertiary strata of Bijou Basin, forty 

 miles east of Denver, Colorado. This indicates the extension of open-sea 

 marine deposits much farther into the interior of the continent during the 

 Tertiary period than has been previously known. 



Upon following pages I present a classified catalogue of all the inver- 

 tebrate species, following which are descriptions of the new species. This 

 catalogue enumerates two hundred and sixty-two species in all, forty-eight 

 of which are new to science, and described herein for the first time. 



Very respectfully yours, 



C. A. WHITE. 

 Professor J. W. POWELL, 



Geologist in charge of the Second Division United States 



Geological and Geographical Survey of the Territories. 



GENERAL OBSERVATIONS. 



The fossils of the collections of which the following pages are occupied 

 in large part by a classified and partially descriptive catalogue, have been 

 obtained from strata of the Carboniferous, Triassic, Jurassic, Cretaceous, and 

 Tertiary periods ; very largely from the immediate vicinity of the Green and 

 Colorado Rivers and from portions of Northern Utah and Southern Wyom- 

 ing. The areas from which they have been collected are very small com- 

 pared with that of the great Plateau Province, the study of the invertebrate 

 paleontology of which the preparation of this report is only a beginning. 

 It is, therefore, too early to draw final conclusions concerning the general 

 lessons which full collections from that great region will be sure to teach 

 us, or to deduce at present, any very satisfactory generalizations; but it 

 may not be unprofitable to mention some of the facts, in their order, that 



