OOLITE. 



FIG. 47. 



Pentacrinites Iriareus. 



showing an advance of or- 

 ganization from those of pre- 

 ceding systems. The pentacri- 

 nite, instead of a round, has a 

 five-angled stalk, with an in- 

 creased profusion of tenta- 

 cula ; it has also the superior 

 character of a power to float 

 about, and attach itself where 

 it pleased. To this fossil of 

 the lias succeed others of the 

 same group in the oolite 

 comatula and ophiura which . 

 are entirely free-swimming, 

 thus supporting the general 

 appearances of an advance of 

 animal characters as we pro- 

 ceed from lower to higher for- 

 mations. Here also appear 

 other examples of the order 

 to which the crinoidea belong 

 (echinodermatd) ; namely, the 



FIG. 48. 



Comatula rosacea (recent). 



