Occasional Papers of the Museum of Zoology 9 



tion of the north and south branches of James Creek, there 

 are three ponds, the largest of which probably covers two or 

 three acres. The smallest of these becomes dry in July and 

 August, but the other two are perennial at the present time, 

 probably primarily because a ditch has been dug to them from 

 the north branch of James Creek so that they are enlarged in 

 times of high water. They are strongly alkaline. The only 

 other perennial body of quiet water in the region is a small 

 lake, about one-fourth of a mile in diameter, in the Cortez 

 Range. This lake was not studied. 



Vegetation. 



A brief description of the vegetation will be sufficient. The 

 sagebrush covers the whole area from the margin of the Hum- 

 boldt Valley to the summit of the ranges (PI. I, Fig. 2; PI. II. 

 Fig. 2; PI. Ill, Fig. i). On the mountains it is smaller and 

 more mixed with other plants, such as Balsamorhiza sagittata, 

 and a few junipers (Juniperus utahensis Lemm.) and shrubs, 

 and in the valley of the Humboldt and in the mouth of the 

 valleys of the Maggie, Annie and Susan Creeks it is replaced 

 by a zone of CJirysothamnus pinifolius Greene, and this along 

 the streams by a zone of grasses (principally Elymiis conden- 

 satus). On the salt-spots shrubs of the genus Atriplex are 

 dominant. 



Along the permanent streams and a few of the irrigation 

 ditches on the basin floor there are clumps of willows and 

 numerous shrubs (PI. I, Fig. i), and in the mountain canyons 

 there are small groves of poplar, buffalo berry and other small 

 trees and shrubs (PI. Ill, Fig. i). 



Habitats and Habitat Distribution. 

 The differences in topography, soil and vegetation provide 

 a number of reptile and amphibian habitats which may be listed 

 as follows : 



