Life of Upper Lake Region. 133 



extending several miles southeastward, the 

 channel of the river being excavated through 

 it. It will be remembered that we called the 

 Miocene lake beds the Lower lake deposits. 

 These of the second group we will call the 

 Upper lake deposits and apply to them the 

 term Pliocene. This Upper John Day lake 

 sedimeni, then, is to be with us the type of 

 the group. 



Another Pliocene lake covered a large por- 

 tion of the depression along which the Sho 

 shone or Snake river now flows; a third of 

 these lakes covered the place now occupied 

 by the city of The Dalles; a fourth lake ex- 

 tended north and west from Walla Walla into 

 the Yakima valley; a fifth occupied the de- 

 pression now ^covered by Klamath lake and 

 marsh. Two characteristic fossils run through 

 all these lake sediments of the Pliocene period, 

 the camel and the horse. 



HIPPARION. 



If we look for the record of the horse type 

 in this new chapter, we shall find a wonder- 



