PLATE 8 



Fig. 1. Big Creek Eanch (Camp no. 1, 4350 feet altitude) aud neigh- 

 boring desert, the Pine Forest Mountains in the background, Humboldt 

 County, Nevada; June 22, 1909. The poplars about the ranch were intro- 

 duced. The meandering course of Big Creek is marked by a line of 

 willows and alders. Big Creek Caiion is noticed on the right. The brush 

 in the foreground is principally Chrysothamnus, Grayia, and Artemisia 

 tridentata. Mammals inhabiting this association include Citellus mollis, 

 Peromyscus maniculatus sonoriensis, Perodipus microps levipes, Eutamias 

 picUis, Onychomys hrevicaudus, Perognathus parvus olivaceus, Lepus cali- 

 fornicus wallawalla, Sylvilagus nuttalli grangeri and Taxidea taxus. The 

 commonest reptiles are Crotaphytus wislizenii, Cnemidophorus tigris, Scel- 

 oporus graciosus, and TJta stanshuriana. 



Fig. 2. View up Big Creek from Camp no. 2 (see map, pi. 7), 6000 

 feet altitude. Pine Forest Mountains, Humboldt County, Nevada; July 7, 

 1909. The trees along the stream are aspens, alders and willows. Arte- 

 misia tridentata is the chief plant on the Big Creek flats. The dark 

 patches on the high ridge are made up of Populus tremuloides. The sage- 

 brush flats are areas of admixture of Transition and Upper Sonoran 

 species, while the animals found along the stream were chiefly Transition 

 in distribution. Sceloporus graciosus, Perognathus parvus olivaceus, and 

 Citellus oregonus were fairly common in the vicinity of this camp. 



[42S] 



