106 Introduction to Life of the Lakes. 



Inasmuch as our Shoshone island was yet 

 separated from the continent during the 

 Eocene period, the mammalia did not yet 

 reach that region. But as the whole coast 

 continued to rise above the sea level - there 

 came a time when one of the eastern spurs 

 of the island reached the main land and joined 

 the continent. This came to pass at the close 

 of the Eocene period, and at once the way 

 was opened from the Rocky mountain region 

 to Shoshone. 



The larger mammals soon discovered this 

 and its first pioneers swarmed into the new 

 region of our future Oregon. The remains of 

 these migrating bands of mammalia are now 

 found in Eastern Oregon buried in old lake 

 beds, the soft oozy mud of which received 

 them from the wash of the mountain streams 

 and effectually preserved them from decay. 



The fact that these fossils are found in lake 

 sediments furnishes no proof that the animals 

 to which they belonged were water animals, 

 for although many of them were such, a much 

 larger number were land animals. This result 



