430 ENTROCHAL MARBLE. 
an almost endless extent by examining the pe- 
culiarities of each part throughout their numerous 
species. We may judge of the degree, to which 
the individuals of these species multiplied among 
the first inhabitants of the sea, from the countless 
myriads of their petrified remains which fill so 
many Limestone beds of the Transition For- 
mations, and compose vast strata of Entrochal 
marble, extending over large tracts of country in 
Northern Europe and North America. The sub- 
stance of this marble is often almost as entirely 
made up of the petrified bones of Encrinites, as 
a corn-rick is composed of straws. Man ap- 
plies 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 millions of organized beings, once 
endowed with life, and susceptible of enjoy- 
ment, which after performing the part that was 
for a while assigned to them in living nature, 
have contributed their remains towards the com- 
position 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 be- 
fore the deposition of the Lias, and only one 
* Fragments of Encrinites are also dispersed irregularly 
throughout all the depositions of this period, intermixed with the 
remains of other cotemporary marine animals. 
