A GEOLOGICAL SITUATION IN THE LAVA FLOW, 
WITH REFERENCE TO THE VEGETATION. 
BY HARRIET M. CLEARMAN. 
This great lava flow extends over a great part of Idaho, 
Washington, and Oregon. The area covered is extensive, 
some 200,000 square miles. That this flow has consider- 
able depth may be seen at Shoshone Falls, and at various 
places where the river has cut a gorge. That there were 
successive flows with intervals of rest between may also 
be seen by a river gorge, for in the walls, are fossil roots 
and stumps. Further than this but little has been written 
concerning this wonderful field. 
To those who know the character of this region I shall 
need to offer no apology for the . inadequateness of my in- 
vestigations. The chief obstacles to the work were, 
first, the lava, which was utterly impassable in many places; 
second, the lack of water; and third, that the region had 
not been surveyed. The distances consequently are only 
approximate, and the whole investigation which was made 
in 1899 and 1900 is merely offered as a suggestion. 
In Idaho the Snake river flows entirely in the lava 
region; and from near the source to beyond Shoshone Falls, 
more than one-half the distance across the State, about 
450 miles, there is no tributary from the north. Here are 
a number of volcanic buttes but they could hardly be the 
source of so vast a quantity of lava, so the theory of earth 
fissures should hold good here. 
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