Vol. XXV, pp. 3-8 January 23, 1912 



PROCEEDINGS 



OF I II I 



BIOLOGICAL SOCIETY OF WASHINGTON 



NOTES ON THE DISTRIBUTION OF SOME COLORADO 



MAMMALS. 



BY EDWARD R. WARREN. 



During the summer of 1**11 T made a somewhat extended 

 collecting trip by wagon through north-central Colorado, accom- 

 panied by Mr. H. R. Durand as assistant. Work was first done 

 on the plains ami " Divide : ' region as far east as Cedar Point, 

 Elbert County, and then turning westerly and northerly as far 

 as Pawnee Buttes, and thence westerly again, the mountains 

 were reached by way of Log Cabin, Elkhorn and Chambers 

 Lake, and the Medicine Bow Range crossed by way of Cameron 

 Pass into North Park, which was set off as Jackson County two 

 years ago. Most of the work was done on the west side of the 

 Park, ami then Buffalo Pass crossed to Steamboat Springs, and 

 the return to Denver was via Core and Berthoud Passes. The 

 collections made on this trip resulted in greatly extending the 

 known range of one species of chipmunk, and add something to 

 our knowledge of the distribution of two others; another record 

 of Phenacomys was added to the very few Colorado occurrences 

 of that genus; certain other notes were made which seem 

 worthy of record, and I have added some notes lately made by 

 myself in other portions of the State, besides the two records of 

 Nj/cteris bdrealis which I am permitted to publish herewith and 

 for which due credit is given under that species. 



I am under obligation to the Bureau of the Biological Survey 

 for the identification of the specimen of Phenacomys. Mr. Durand 

 kindly loaned for comparison some specimens collected by him- 

 self on the expedition. 



2— Pp.oc. Biol. Soc. Wash., Vol. XXV, 1912. (3) 



