The Shoshone Island. 79 



These broader sheets of lava seem to have 

 been thrown out in the earlier stages of the 

 period of eruption and to have left their traces 

 along the eastern slopes of the range, while 

 the later, narrower and shorter outflows built 

 up more rapidly westward of the axis of the 

 upfold. I recall an impression I once received 

 of the enormous thickness of some of these 

 lava deposits on the DesChutes river east of 

 the Cascade range. 



At about thirty miles from The Dalles the 

 old Canyon City road crosses the DesChutes. 

 In its descent from the DesChutes hills the 

 road was cut into the face of the hill, giving 

 a good exposure of its rocky materials. It 

 was thus seen that in the upper part of the 

 hill, loose materials, held in place by an occa- 

 sional dense lava flow, characterized the road 

 through a descent of sixteen or eighteen hun- 

 dred feet. The remaining part of the road 

 was simply a climbing down across the escarp- 

 ments of twenty-seven to thirty well marked 

 flows of lava, ranging in thickness from 

 twenty to fifty feet and aggregating not less 



