Allen.] 36 [June 3, 



and give the country, when seen at a distance, the appearance of 

 being quite thickly wooded. The distribution of the pines serves to 

 mark the extent of the tertiary sandstones, the pines abruptly disap- 

 pearing with the appearance of the cretaceous clays and marls. 



With these preliminary remarks descriptive of the general charac- 

 ter of the country, we proceed to give in detail such observations as 

 our rapid journey of nearly one thousand miles in less than one hun- 

 dred days, including detentions, enabled us to make respecting the 

 vertebrate fauna of the district through which we passed. Although 

 we moved quite too rapidly to allow of a very satisfactory examina- 

 tion of the country traversed, or to admit of the formation of very 

 large collections, it is believed that but few species escaped notice, 

 while of the greater part specimens were either preserved or ex- 

 amined. 



In this connection it gives me great pleasure to acknowledge 

 my indebtedness to my valuable assistant, Mr. C. W. Bennett, for 

 important aid in my work, and for many facts recorded in the follow- 

 ing pages. Mr. S. H. Scudder has kindly prepared the report on the 

 butterflies, and Dr. Geo. Vasey, botanist of the Department of Agri- 

 culture, has prepared the report on the plants, with which I have 

 incorporated a few remarks on the relative abundance and range of 

 some of the more prominent species. The report on the fishes is 

 unavoidably delayed. 



II. Report on the Mammals. 



Although the region now under consideration is so barren, and has 

 hitherto been so little frequented by white men, considerable changes 

 in the relative abundance of the larger mammals have already been 

 effected by human agency. The buffalo that once swarmed over 

 these plains has wholly disappeared east of the Yellowstone, as far 

 up at least as the Tongue River, and with his decline have nearly 

 disappeared the coyote and the wolf. The elk and the black-tailed 

 deer were formerly abundant along all the principal streams, but 

 neither now occurs in any numbers except on the Musselshell, and 

 on the Yellowstone above the mouth of Powder River. The moun- 

 tain sheep, or bighorn, still occurs sparingly in the Bad Lands bor- 

 dering the Little Missouri and Yellowstone Rivers. The pronghorn 

 is the only one of the herbivores that is still generally distributed, 

 being now the most numerous of the larger mammals. A very fatal 

 disease, however, visited them the past summer (1873), sweeping 



