Animals Before Man 



poorly represented nowadays compared with 

 what it was in the past, when it was not 

 only far richer in species but individuals were 

 vastly more abundant ; also they seem to have 

 flourished in far shallower waters than at 

 present. So numerous were they, and so thick- 

 ly did they grow, that some extensive beds of 

 limestone seem to have been mainly formed 

 by crinoids, and are so full of their fragmen- 

 tary stems and arms as to have received the 

 name of crinoidal limestone. The abundance 

 of crinoids may be inferred from the fact that 

 over one thousand species have been described 

 from the Carboniferous rocks of North Ameri- 

 ca,* and we can picture to ourselves the quiet 

 depths of the sea as thickly covered wdth 

 graceful sea-lilies as the rocks of the waters 

 along our New England coast are clad ^^A\h. 

 seaweeds. How such profusion of life would 

 now rejoice the heart of the collector ! How, 

 in fact, it does rejoice his heart, for though 

 the bed of the Carboniferous ocean be worked 



* About one-third of the known species of invertebrates in the 

 Carboniferous rocks of North America are crinoids. 



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