116 



HISTORICAL GEOLOGY 



builders. Their lack of abundance may be somewhat apparent 

 only, due to the fact that more delicate forms prevailed. 



Fig. 65 

 A Silurian Eurypterid, Eurypteris remipes, restored to show 

 dorsal side. (After Clarke and Ruedemann, N. Y. State 

 Mus. Mem. 14.) 



Brachiopods continued to be the most prominent of all organ- 

 isms as regards both number of individuals and species, and this in 

 spite of the fact that very few Ordovician species, and not many 

 genera, continued from the Ordovician into the Silurian. Two 



