144 Life of Upper Lake Region. 



There is a curious piece of geological his- 

 tory brought to the front in endeavoring to 

 explain the circumstances under which this 

 gray sandstone of The Dalles group must 

 have been deposited in those far away Plio- 

 cene times. It to-day represents the bot- 

 tom of a former lake. It is two hundred and 

 fifty or three hundred feet above the present 

 level of the Columbia river. The river has, 

 in excavating its present bed, washed away 

 the whole of that lake bed excepting this 

 sandstone remnant, and worn its way through 

 over two hundred feet of solid basalt besides, 

 in reaching its present level. The east and 

 south borders of this lake sediment are con- 

 cealed by a covering of glacial deposit, under 

 which it may be traced eastward two or thrc(e 

 miles. It was from this eastward extension 

 of the rock that the small Auchenia fragment 

 of radius was found, and from this same gray 

 sandstone Mr. D. H. Roberts obtained the 

 distal end of a well defined metacarpal bone 

 of a larger Auchenia, perhaps the Vitakeri 

 elsewhere noted. 



