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LETTER XIX. 



CAP ENCRINITE OF DERBYSHIRE, AND, PERHAPS, OF YORKSHIRE.... 

 SUPERIOR TERMINATION. ..SUPPOSED INFERIOR TERMINATION.... 

 TURBAN ENCRINTTE OF SH ROPSH I RE....PELVI S DECRIBED IN- 

 FERIOR EXTREMITY PECULIARITY OF ITS TR U NK....S AME CO- 

 LUMN FROM GOTHLAND. 



THE species of encrinus to which I shall now lead your attention, 

 is one which, although its remains are most extraordinarily abundant 

 in our own country, its history is, perhaps, least of all known to usi 

 Indeed we at present know little more of it than, that the petrified re- 

 mains of its vertebral column, either in detached pieces, or aggluti- 

 nated together in masses of limestone or marble, have long been 

 found in quarries of an immense extent in some of the northern coun- 

 ties of this island. 



Mr. Da Costa remarks, that the whole metallic tract of the 

 county of Derby is, as it were, one continued quarry of this mar- 

 ble ; most of the strata of limestone are of this kind, it being the 

 common stone which is burnt for lime. The upper parts of these 

 strata, he observes, are always filled with amazing quantities of 

 these bodies and other marine remains, which seem to have been lodg- 

 ed there by subsidence; and to have formed a crust over the lime- 

 stone. This crust is generally of a very great thickness, and when 

 they have passed it, they find the limestone to contain fewer marine 

 remains : and at greater depths it even becomes quite pure and free 



