322 University of California Puhlications in Zoology. [Vol. 7 



cross-section completed. It will, of course, have been noted that 

 the cross-section is not an ideal one. To make it so an equal 

 amount of time should have been spent at each locality. Practical 

 difficulties, however, made this impossible. Furthermore, sea- 

 sonal change, even within the short space of time covered in the 

 cross-section series of camps, affects the distribution of certain 

 forms, particularly birds, and so ideally these localities should 

 all have been worked at the same time. 



On July 29 we departed for Leonard Creek, making camp at 

 6500 feet altitude, and remaining until August 10. On this date 

 we returned to Big Creek Ranch, and prepared our outfit for 

 transit back to the University. Practically three months were 

 occupied in actual collecting. 



DESCRIPTIONS OF LOCALITIES 

 (Eefer to map, plate 7) 



The following localities were visited either by members of the 

 palaeontological party or by our expedition. 



Willow Point, Amos (Cane Springs Station), Sod House 

 Point, and Tregaskis Well (fourteen miles south of Quinn River 

 Crossing) are successive stage stations between Winnemucca and 

 Quinn River Crossing. Chimney Creek is a stream flowing west- 

 ward out of the Santa Rosa Mountains east of Amos. 



Virgin Valley is located northwest of the Pine Forest Moun- 

 tains over a low range of hills (see map). Thousand Creek flows 

 northeast out of Virgin Valley. It is situated some twelve miles 

 north and a little west of Alder Creek Ranch. Soldier Meadows 

 is located on an arm of the Black Rock Desert, and is forty 

 miles due south of Virgin Valley. Little High Rock Caiion is 

 west and a little south of Soldier Meadows, being just over the 

 Humboldt County line in Washoe County. 



Mason's Crossing or Quinn Biver Crossing (altitude 4100 

 feet). — This locality is situated in the midst of the open desert 

 on the Quinn River. The stream is in this region strongly 

 alkaline and follows a winding course in a general westerly 

 direction, soon turning toward the southwest and flowing into a 

 sink on the Black Rock Desert. 



Toward the east appears a series of low, desert hills, which 



