52 A GEOLOGICAL HISTORY. 



exhibit by Mr. Furman of Brooklyn, Long Island, 

 and it was said to have been found (in digging a 

 ■well) sixty feet below the surface ; the specimen 

 was very perfect, having both valves and some of 

 the earthy matter of the Green Sand adhering to 

 it — the only perceptible difference was, that the 

 earthy matter was rather finer and had more 

 shining specks of Mica than the Green Sand of 

 New Jersey has — if this prove true, the establish- 

 ment of Green Sand underlying Long Island is 

 made out. It has been often said that quantities 

 of large oyster shells have been taken from the 

 bottom of deep wells on the island ;* the Exogyra 

 and Gryphaea so much resemble our common 

 oyster that almost all persons who are not unac- 

 quainted with Conchology call them so. 



8th Tertiary.— {Plate 3, Jig. 8.) The Tertiary 



* While I was writing on this subject, my friend, Dr. Samuel Akerly, 

 came to my house, and after examining the fossil exhibited at the Lyceum, 

 he confirmed the identity of the Green Sand on Long Island, by telling 

 me that Dr. Samuel L. Mitchill had received the same fossil (Exogyra 

 Costata) from Long Island, (between Brooklyn and Flatbush,) it was ob- 

 tained from the bottom of a well which Mr. was digging, many 



feet below the surface. 



Dr. Swift, of the U. S. Navy, exhibited, as I understand from good 

 authority, shells and pebbles of ancient sea-beach, taken from the bottom 

 of a well dug on Long Island for the use of the United States Naval 

 Hospital. What is remarkable, the workmen had to blast through a 

 boulder in carrying on their operations. The shells were so weathered and 

 water-worn that nothing could be determined as to their geological age. 



