264 DOMAIN III. ARGILLACEOUS. 



Pale blue, with cubic pyrites, from Yorkshire. 



The same, with dendritic pyrites. 



The same, singularly convolved, from the Alps 

 of Dauphiny, and many other regions. 



Thick clay slate, intersected in all directions 

 with veins of quartz, from Scotland. 



The same, with calcareous spar, from Durham. 



The same, with veins of quartz containing eme- 

 ralds, from the celebrated emerald -mines at Muzo, 

 in the Viceroyalty of New Grenada. It does not 

 appear that Peru ever produced any emeralds. 



Massive clay slate, or perhaps rather clay rock, 

 from "Ronneburg. 



Clay slate, in rhomboidal fragments, from Dit- 

 terbach. 



Thick clay slate, with a coarse-grained earthy 

 fracture, from Upper Lusatia. 



Green clay slate, with calcareous spar, from 

 Shneeberg. 



The same, with cinnabar, from Idra. 



Clay slate, with yellow blend, from Transyl- 

 / vania. 



From the Specimens of clay slate, collected on the river 



Ganges. 



Ganges, and its vicinity, by Colonel Hard wick, 

 on his journey to Siranagur. 



Clay slate, from the rocks about Ghinouly. 



The same, of a silky appearance, and seemingly 



