324 PHYSIOLOGICAL CONSIDERATIONS. 



the degree, to which the individuals of these species multi- 

 phed among the first inhabitants of the sea, from the count- 

 less myriads of their petrified remains which fill so many 

 Limestone beds of the Transition Formations, and compose 

 vast strata of Entrochal marble, extending over large tracts 

 of country in Northern Europe and North America. The 

 substance of this marble is often almost as entirely made up 

 of the petrified bones of Encrinites, as a corn-rick is com- 

 posed of straws. Man applies it to construct his palace and 

 adorn his sepulchre, but there are few who know, and fewer 

 still who duly appreciate the surprising fact, that much of 

 this marble is composed of the skeletons of milhons of orga- 

 nized beings, once endowed with life, and susceptible of en- 

 joyment, which after performing the part that was for a 

 while assigned to them in living nature, have contributed 

 their remains towards the composition of the mountain 

 masses of the earth.* 



Of more than thirty species of Crinoideans that prevailed 

 to such enormous extent in the Transition period, nearly all 

 became extinct before the deposition of the Lias, and only 

 one presents the angular column of the Pentacrinite ; with 

 this one exception, pentangular columns first began to abound 

 among the Crinoideans at the commencement of the Lias, 

 and have from thence extended onwards into our present 

 seas. Their several species and even genera are also limit- 

 ed in their extent ; e. g. the great Lily Encrinite (E. monili- 

 formis) is peculiar to the Muschelkalk,'and the Pear Encri- 

 nite to the middle region of the Oolitic formation. 



The Physiological history of the family of Encrinites is 

 very important ; their species were numerous among the 

 most ancient orders of created beings, and in this early state 

 their construction exhibits at least an equal if not a higher 



* Fragments of Encrinites are also dispersed irregularly throughout all 

 the depositions of this period, intermixed with the remains of other contem- 

 porary marine animals. 



