THE CRETACEOUS PERIOD 



257 



Fig. 158 



Cretaceous Foraminifers, greatly enlarged. (Af- 

 ter Calvin, from Le Conte's " Geology," per- 

 mission of D. Appleton and Company.) 



doubt of their presence — both Monocotyledons and Dicotyle- 

 dons — even in late Lower Cretaceous time. By the close of the 

 period the Angiosperms had developed so phenomenally as to 

 attain a position of 

 supremacy among 

 plants, which position 

 they have maintained 

 ever since. This com- 

 paratively sudden ap- 

 pearance and remark- 

 able development of 

 the Angiosperms "was 

 one of the most im- 

 portant and far-reach- 

 ing biologic events the 

 world has known. . . . 

 So far as we know, this 

 flora appears to have 

 had its origin in eastern or northeastern North America, in the 

 Patapsco division of the Potomac series. Although the great ma- 

 jority of the plants found in associa- 

 tion in these beds, both as regards 

 species and individuals, still belonged 

 to lower Mesozoic types, such as 

 Ferns, Cycads, and Conifers, we find 

 ancient if not really ancestral Angio- 

 sperms. . . . No sooner were they 

 (Angiosperms) fairly introduced than 

 they multiplied with astonishing 

 rapidity and in the . . . Raritan 

 they had become dominant, the 

 Ferns and Cycads having mostly 

 disappeared and the Conifers having 

 taken a subordinate position." 1 No 

 present-day species existed, but, 

 among the more modern genera were 

 Oaks, Elms, Magnolias, Maples, 

 Figs, Laurels, Palms, Grasses, etc. 



1 F. H. Knowlton: In Outlines of Geologic History, by Willis and Salisbury, 

 pp. 205-206. 



Fig. 159 



A Cretaceous Brachiopod, Tere- 

 bratula harlani. Note the 

 curved hinge line. (From 

 Shimer's "Introduction to 

 the Study of Fossils," cour- 

 tesy of The Macmillan Com- 

 pany.) 



