56 A GEOLOGICAL HISTORY. 



seem that the white silvery Talc of this locality 

 took the place of the Hydrate of Magnesia. 



3d Sandstone. — {Plate ^fig- 3.) Indications 

 of this rock shows itself, both on the south of the 

 Island on the Richmond road, and on the north 

 end, near the Trap ; but it is supposed not to have 

 been found in place as yet. 



4th Trap or Greenstone. — {Plate 4, fig. 4.) 

 This rock is the southernmost end of the Pali- 

 sades of the Hudson River : it is generally a better 

 kind to work or dress, than any further north of 

 this locality, quarries have been opened, and large 

 square blocks have been dressed, which show a 

 beautiful and durable material for building, it is 

 erroneously called " Staten Island Granite." 



5th Beds of Pea Iron Ore. — (Plate 4, fig. 5.) 

 These beds I think may be members of the Sand- 

 stone, they can be seen on both sides of the Island 

 near the first corner, where the road runs from 

 the Turnpike to New Brighton or " the Kills ;" 

 and on the road that leads from Tompkinsville to 

 Richmond on the right hand, just before you come 

 to the Moravian Meeting-house. This ore has 

 been mined. 



6th Diluvium. — {Plate 4,fig. 6.) This formation 

 is mostly the same as that of New York and Long 



