Introduction to Life of the Lakes. 103 



wider scope of life forms. The lower lake 

 remains would represent the early and middle 

 Tertiary, the upper the later Tertiary period. 

 The oldest of these lakes may be traced along 

 the lower reaches of the John Day river ex- 

 cavated by the wash and wear of that stream. 

 A southern extension of this lake sediment 

 was laid bare by the drainage of the Crooked 

 river, an eastern branch of the DesChutes. 

 Both of these will be described as lower lake 

 deposits, for they belong- to the same geolog- 

 ical horizon. 



The lowest of these deposits abound in 

 well preserved leaf impressions, many of them 

 equal to the finest engravings, the original 

 carbon of the leaf furnishing the printer's ink. 

 As fitly illustrating these fossils there is intro- 

 duced on Plate V the print of an aralia, a 

 cousin of our thorny panax; and another on 

 Plate VI of some leaves of a cycad, a near 

 relative of salisburia, the Japanese ginco. 



A fine impression of a fan palm was also 

 found in these same rocks a few years since. 

 The palm and ginco required a subtropical 



