26 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
For the most part the Columbia River lava completely covered up 
all of the older rocks over which it flowed, these being seen only as 
they are revealed in the river canyons. Exceptions to this appear in 
peaks which were too high to be overwhelmed, as in the cases of 
Steptoe and Kamiak buttes in Whitman County, together with many 
others less conspicuous. Steptoe Butte is a granitic cone projecting 
about 500 meters above the surrounding basalt and, being completely 
isolated, is a notable landmark. To designate such isolated buttes, of 
which there are many, Russell has proposed the term steptoe, after 
the name of this striking example. A steptoe is “ an island of granite 
-n a sea of basalt.” Kamiak butte near Pullman is composed 
largely of quartzite. 
THE BLUE MOUNTAINS. 
The Blue Mountains in extreme southeastern Washington and ad- 
jacent Oregon, represent a great uplift of basalt surrounding : 
central mass of granite peaks. The portion of these mountains in 
Washington is composed wholly of basalt, elevated to over 2,000 
meters. 
The granitic peaks in the central part of the mountains, the so- 
called Powder River Mountains in Oregon, rise to an altitude of 
about 3,000 meters, and form the greatest “steptoe” in the whole 
Columbia Basin. 
CLIMATE. 
The data here presented are compiled from the reports of the 
United States Weather Bureau. The observing stations are all 
located at places of relatively low altitude, and the accurate data 
therefore relate wholly to the portions of the State which lie in the 
Transition and Upper Sonoran areas. 
PRECIPITATION. 
The following table gives the normal annual rainfall of each of 
the Weather Bureau stations together with the length of the period 
over which full records are available: 
