The Shoshone Island. 83 



tunate enough to find one. At a place under- 

 mined by the DesChutes river, I found a fine 

 section of the bank with about ten feet of the 

 condensed volcanic ash covering seven feet of 

 dark rich soil with traces of other times. 



This recent instance of volcanic eruption 

 of volcanic ashes furnishes an impressive les- 

 son in geology, showing as it does the extent 

 to which such volcanic products were capable 

 of modifying the sediments of the waters of 

 this region during the early Tertiary times. 



But this work of covering the hill sides 

 with showers of soil capable of sustaining for- 

 ests of pine, was not the only notable result 

 by which these showers of ashes may be 

 traced. The prevailing winds were westerly 

 and the drift of ashes to the eastward, and this 

 being a country of many lakes in the times we 

 are describing, much of this volcanic ash 

 would fall on these lake surfaces and become 

 an evenly distributed sediment, covering up 

 and so preserving the remains of bird and 

 beast in stratified volcanic ashes. A very in- 

 teresting example of this kind one finds near 



