94 



they may be divided. The fracture is like other compact 

 calcareous marles, that are not governed by the conical 

 formation. We have had them from two or three friends 

 in Derbyshire. The present specimen was given me by 

 Mr. Baker, by favour of my friend the Rev. James Dalton, 

 and comes from the alum-works at Boulby in Yorkshire 

 belonging to the former gentleman, and was remarked for 

 being in the form of a horse's hoof, having settled upon a 

 Cornu-Ammonis. 



They are mostly of an argillaceous marie: but I have one 

 from Cumberland, given me by Mr. Buchanan from Barton 

 fell, which seems to be more of an Iron ore than any of 

 my others. In most of the English specimens the cones 

 are rather confusedly coalesced. In foreign ones, groups of 

 cones joined together by their edges are apt to separate j 

 whence Linnaeus's description. The present specimen 

 figured contains so much pyrites dispersed through it, that 

 it miffht be used as an alum ore. 



