2 University of Michigan 



tiles and amphibians was the principal work of the writers, but 

 considerable assistance was received from the other members 

 of the party. 



General Location of the Region. 



The area studied is about the town of Carlin, Nevada, in 

 the western part of Elko County and northern part of Eureka 

 County. It includes the basin of ISIaggie Creek south of 

 Maggie Canyon, the valley of the Humboldt River between 

 Moleen Canyon and the Cortez Range, the east side of the 

 Cortez Range, and the parts of the Seetoya, River and Pinyon 

 Ranges which border on the basin. About all of the major 

 habitats characteristic of the general region are probably rep- 

 resented in this area, with the exception of those above 8,000 

 feet. 



The boundaries of the region chosen for study were so 

 drawn that many habitats were included in an area which 

 could be examined carefully in the time available. An effort 

 was then made to discover every locality where representatives 

 of the groups which were to receive careful study were living, 

 and these were visited many times, so that an exhaustive col- 

 lection of species and detailed data on habits, habitats and 

 local distribution might be obtained. 



Climate. 

 The region is arid. The mean annual precipitation is about 

 7.22 inches ; there may be as little as 2 inches in one year, and 

 much of it is in the form of snow. As a rule more than half 

 of the precipitation occurs between December and March and 

 over 80% occurs between November and May inclusive. There 

 is a high percentage of clear skies. During the summer months 

 high temperatures are frequent, but there are large diurnal 

 variations so that the nights are generally decidedly cool and 



