24 NORTH AMERICAN FAUNA [No. 55 



The Steens Mountains, typical of the Great Basin type of arid 

 ranges, are practically devoid of timber and show much distorted 

 zone levels. Owing to the high base level of approximately 4,000 

 feet on the east side and 4,500 feet on the west side of the range, 

 the zones are pushed to unusual heights. Transition Zone, as nearly 

 as it can be defined, reaches from about 4,200 to 6,000 feet on the 

 northeast slopes and from about 5,000 to 7,000 feet on the southwest 

 slopes. On the very steep eastern slope of the range there is much 

 crowding and overlapping of the zones, and a general narrowing of 

 Transition and Canadian. 



MAMMALS, BIRDS, AND PLANTS 



The mammals most characteristic of the arid Transition Zone are, 

 or have been, the desert mountain sheep, Rocky Mountain mule 

 deer, Idaho rabbit, woodchuck (Marmota flaviventris avarcti , and 

 pygmy mouse (Microtus pcmpemmus). 



Its characteristic birds are the sage grouse, Brewer's sparrow, 

 green-tailed towhee, and sage thrasher. 



It is practically treeless except for the low mountain-mahogany 

 and some of the high-ranging junipers (Jwiiperus ocddentalis and 

 scopulorum), which often ascend through it. Generally, it is char- 

 acterized by open sagebrush slopes well covered with sagebrush 

 (Artemisia tridentata, arbuscula^ and trifida), Balsamorhiza sagit- 

 tata, Wyethia (miplexicaAdis^ and Paeonia brownii. 



Agriculture in this arid division of Transition Zone is practically 

 limited to stock raising, mainly summer grazing of sheep and cattle. 

 Where water is available for irrigation, there are ranch gardens and 

 some hay, but water is scarce, and in the dry climate frosts are 

 frequent during even the summer months. Ranches are few and far 

 between and generally control extensive areas of grazing land. 



CROP ADAPTATIONS IN TRANSITION ZONE 



While little agriculture, except an occasional irrigated garden, is 

 attempted in the arid Transition Zone, the semihumid bench land of 

 this zone in the Blue Mountain section and along the eastern side 

 of the Cascades produces excellent small-grain and potato crops, in 

 most cases without irrigation. Still better crops of grains, potatoes, 

 alfalfa, and some fruits, however, are grown where irrigation is 

 possible. 



In the humid Transition Zone west of the Cascades a great variety 

 of crops are raised small grains, wheat, oats, rye, barley, peas, hops, 

 clover, vetch, timothy hay, potatoes, vegetables, nuts, and fruits in 

 profusion. Most of the valleys are famous for their flowers, roses of 

 wonderful beauty and variety, gladioli, dahlias, and a great variety 

 of hardy flowering plants. Each valley and every section of a valley 

 have slightly different climatic conditions, and with the varying soil 

 and humidity each one shows special adaptations that cannot be 

 covered by any generalized lists of crops. The only safe course for 

 the grower in selecting crops of special advantage in each location 

 is to follow the advice of the local county agents, the State agri- 

 cultural college, and the experiment stations. 



