1890.] NATURAL SCIENCES OF PHILADELPHIA. 161 



nearly one-lialf the size it possessed in the Keokuk, notwithstand- 

 ing the fact that this species had perhaps a wider geographical range 

 than any other congeneric form occurring within the Mississippi basin 

 and was therefore better adapted to preserve its full vigor, at least 

 in some parts of its distribution. 



The changes in the broad mediterranean sea that once spread over 

 the interior of North America have been referred to elsewhere' in 

 connection with the striking structural features of the crinoids of the 

 Carbonic period and will also be considered in detail in another 

 place. 



Stratigraphical Catalogue. 



carbonic. 



Lower Carbonic. 



Capulus piso (Walcott). 



occidens (Walcott). 



Kinderhook Beds. 

 Capulus formosus (Keyes). 



lodiensis (Meek). 



parcdius (White & Whitfield). 



subpiicatus (Meek & Worthen). 



corniiformis (Winchell). 



haliotoides (Meek & Worthen). 



Burlington Limestone. 

 Capulus biserialis (Hall). 

 cyrtolites (McChesney). 

 equilateral is (Hall). 

 fissurella (Hall). 



infundibulum (Meek & Worthen). 

 latus (Keyes). 

 obliquus (Keyes). 

 quincyensis (McChesney). 

 tribulosus (White). 



Keokuk Shales and Limestones. 



Capulus acxdirostris Hall. 

 equilateralis (Hall). 

 fissurella (Hall). 



1 Keyes : Genesis of the Actinociinidae, Am. Nat., vol. XXIV, p. 243, ft seq. 

 1890. 



12 



