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an equal portion of whiteness, possess even some degree of transparency. 
Besides the difference of appearance proceeding from the nature of 
the calcareous impregnation, a considerable difference arises from 
the combination of other animal remains with those of the encrinus, 
a circumstance seldom occurring in the Derbyshire or Yorkshire 
masses. These other animal remains, which nearly equal in quantity 
the remains of the encrinus, are of the coral kind ; chiefly of 
small, elegant, ramose milleporaj, mingled with fragments of the 
Tubipora Catenulata, and with other marine remains, the natures 
of which are not to be correctly ascertained. Much of this dif- 
ference of appearance also depends on the different characters of the 
remains of the encrini themselves, as will appear from the following 
remarks. 
The fragments of the vertebral column are almost all composed of 
vertebrae which are exceedingly thin, and disposed in a series, in which 
very thin vertebrae alternate with those which are less so, the latter 
projecting a little beyond the former ; so that the column is transversely 
ridged in a regular and elegant form, similar to what is represented 
at Plate XV. Fig. 7- 
The vertebral columns in the specimens I possess are marked by 
charactei-s which seem almost certainly to point out a specific difference 
between the encrinite to which they belong, and those which have been 
already examined. Extreme thinness ot the vertebral trochites is a 
character which, alone, seems to be sufficient to separate the animal 
of this species from those already noticed ; this property being observable 
in every part of the vertebral column which I have seen. From a 
careful examination of the two masses of these remains which I possess, 
I was much pleased to discover that the one was chiefly composed of 
the fragments of ossiculse which had belonged to the superior, whilst 
the other was almost entirely made up of the remains of the inferior 
part of the animal. To the investigation of the characters which these 
possess I now claim your attention. 
