REPORT ON THE NATURAL HISTORY OF THE UNITED STATES 

 GEOLOGICAL AND GEOGRAPHICAL SURVEY OF THE TERRI- 

 TORIES, 1874. 



By Ernest Ingersoll, Zoologist. 



New York, March 1, 1876. 

 Sir : I herewith forward the subjoined report of zoological work done 

 during the season of 1874 in connection with tlie survey under your 

 direction, a preliminary account of which was published by you in the 

 Bulletin of the Survey, second series, No. 2, under date of May 14, 1875 ; 

 and I remain, with high respect, yours, etc., 



ERNEST INGERSOLL, 



Zoologist. 

 Dr. F. V. Hayden, 



U. 8. Geologist, Washington, D. (J. 



The material herein reported upon consists of two collections, chiefly 

 of mollusks: one made by Mr. E. A. Barber, of West Chester, Pa., in the 

 northwestern part of the Territory ; and the other made by the writer 

 in connection with the Photographic Division of the Survey during July, 

 August, and September of 1874, in which he was assisted by Master- 

 Frank Smart, of Washington. 



Mr. Barber was attached to Mr. Marvine's Topographical Party, and 

 collected plants and shells in North Park, along Bear and White Rivers, 

 and at the White River agency, where he was engaged in making baro- 

 metric observations for several weeks. His collection is not large, but 

 is interesting in that it exhibits several species which, 1 did not find, 

 and also includes additional examples of the new Microphysa, which was 

 described by Mr. Bland from my specimens. 



My own route lay from Denver west into Middle Park, thence south 

 up the valley of the Blue to Hoosier Pass, leading the party into South 

 Park, from which we crossed over to the Arkansas, and thence through 

 Poncha Pass into San Luis Park, and across to Saguache. From here 

 the road led west to the Los Pinos Indian agency, and then southwest 

 through Antelope Park to Baker's Park, in the high mountains. 



At this point, the camp was stationed ; and leaving Mr. Smart to col- 

 lect here, I accompanied Mr. Jackson on a side-trip of nearly three 

 weeks' duration, made southwest into the valley of the Rio San Juan, 

 at the extreme corner of the Territory. On our return trip from Baker's 

 Park, we followed the Rio Grande to Del Norte, thence struck across 

 the San Luis plain to the " sand-hills," through Mosca Pass, Huerfano 

 Park, Wet Mouutain Valley, and Oak Creek, and finally came to Canon 

 City, where 1 left the party. 



Collections were made at nearly every camp on the whole route, and 

 that they do not make a greater aggregate is due to the inexperience of 

 the writer, the haste with which the party moved, and not a little to the 

 comparative scarcity of those objects in which he happened to take the 

 most interest, and most desired to have completely represented. In 

 such cases, in the absence of specimens or affirmative evidence, a cer- 



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