192 



THE CHAIN OF LIFE. 



types ; and it is re.narkable that some of them appea** to have 

 continued without even specific change from tlie later Cre- 

 taceous up to the present time. A striking illustration of this 

 is afforded by two ferns d'scover^d side by side id the oldest 

 Eocene beds i of the plains west of Red River, and described 

 in Dr. G. M. Dawson's report on the 49th parallel. Oni 

 of these is the well-known and very common Onoclea 

 s'-nsibilis (Fig. 157), or sensitive fjrn of Eastern America. - 



Fig. it^.—Dinallia tenui/olia. Eocene.— After Dawson. Natural siie and enlarged 



This species came into existence at latest at the close of the 

 Cretaceous, and has apparently been continued in America up 

 to the present time. In Europe, where it does not now live, 

 it occurs as a fossil in Miocene beds in the IbiC of Mull. The 

 other is Davallia tenuifolia (Fig. 158), a delicate little plant 

 belonging to a genus not now represented in America, and to 

 a species at present found only in Asia. Yet this species also 



^ By some regarf"ed as Upper Cretaceous. 



2 First recognised in American Eocene by Newberry. 



