4 NORTH AMERICAN FAUNA [No. 55 



statistics that could not otherwise have been obtained. The infor- 

 mation gathered from ranchmen, hunters, and others along the way 

 has been of great value in supplementing field notes and has been 

 used freely with credit under specific records. 



The natural-history studies of the Mazamas, the mountain-climb- 

 ing club of Oregon, published in annual reports, have afforded val- 

 uable information and have been freely drawn upon, as have the 

 bulletins of the State university, agricultural college, experiment 

 stations, Forest Service, Park Service, and United States Geological 

 Survey. 



While the present report puts on record much that is not commonly 

 known about animal life, it represents a beginning rather than the 

 finished product of studies of the State's mammals. Its greatest 

 value should be in enabling a large number of local people to observe 

 correctly and record the habits of animals until much better under- 

 stood than at present, to know what particular species they are 

 observing, and to obtain definite and accurate information. Much of 

 the animal life is a State and national asset and should be conserved 

 and used to the greatest advantage consistent with wise use and the 

 perpetuation of the species. In some cases this can be done only 

 through the partial or complete control of other species of less value 

 or of destructive habits. Only by applying the most thorough and 

 reliable information can the wildlife of a country be managed 

 efficiently. 



PHYSIOGRAPHIC FEATURES OF THE STATE 



The surface features of Oregon (pi. 1) show wide variation, rang- 

 ing from coastal plains and great inland valleys to broad plateaus, 

 lofty mountain ranges, and snow-capped peaks. Three types of 

 geological formation stand out : The very old non volcanic crystalline 

 or metamorphic rocks, the comparatively recent but still ancient lake- 

 basin deposits of the great valleys, and the volcanic deposits of both 

 ancient and comparatively recent times. 



VOLCANIC AREAS 



A great part of the State, including most of the Cascade Range 

 and the plains to the eastward, is of volcanic origin, consisting of 

 numerous large and small craters and great areas built up by suc- 

 cessive flows of lava. The enormous depth of these lava flows is 

 well shown by the sides of the Deschutes, Columbia, Snake, Grand 

 Ronde, and Imnaha Canyons, by the Kiger Gorge and the east 

 escarpment of the Steens Mountains (pi. 2, J.), and by many other 

 cliffs and canyons in the State. In numerous side walls and rim- 

 rock cliffs consecutive layers of lava, ranging from 20 to 50 feet and 

 sometimes 100 feet in thickness, may be counted to a height or depth 

 of 2,000 or 3,000 feet. Sometimes these form beautiful series of basal- 

 tic columns or layers of royalite, and there are various forms of 

 amorphous lavas, cooled and hardened as they flowed out in surface 

 sheets (pi. 2, B), or in places as shiny black sheets of volcanic glass 

 (obsidian). The vertical cleavage of the lava sheets produces the 



