163 



TAB. CLXXXV. 



SILEX talcum, var. arenaceum. 



Sandy Talc. 



Syn. Mulatto Stone of the Irish. 



This is abundant in the neighbourhood of Belfast, and 

 found under a stratum of Limestone. It is harder than the 

 last, being sufficiently incorporated and indurated to be 

 termed a stone, thus differing from the foregoing, although 

 perhaps containing the same materials 5 viz. Sand and Lime, 

 with, possibly, some Clay, besides Talc. 



The upper figure represents a piece sent by my friend 

 Mr. Templeton, of Belfast, which has the impression of an 

 oyster without any remains of the shell, and that part 

 which seemed to be the impression of the connecting car- 

 tilage of the oyster has the fracture of Carbonate of Lime, 

 There are often, I presume, very curious shells found in 

 this substance ; I, however, have, as yet, only obtained some 

 crushed and unintelligible fragments. The green Talc 

 which spots this stone gives it the characteristic by which 

 it is commonly recognised, and I have often known stones 

 with other greenish substances confounded with it. 



The lower specimen was sent, with others, by Dr. Scott. 

 All had more or less of impressions on them, and mostly 

 of the same animal or shell, something like a curved oyster*, 



* Of these I have some curious small specimens sent by my friend Mr. 

 Wood, from near Wingham in Kent, about ten miles from the sea. There 

 were no vestiges of Chlorite about them. 

 VOL. II. O 



