Niles.l 364 [March 17, 



Mass., who referred to the statement of the occurrence of 

 shells at a great dejjth at Fort Warren, in Boston Harbor, 

 made at the meeting of January 6, 1869, and added similar 

 facts known to him in his own vicinity. 



In reply, Mr. W. H. Niles stated that the occurrence of 

 shells of existing species underneath Fort Warren was of in- 

 terest, not so much because they were found at the mathe- 

 matical depth of one hundred feet below the surface, but on 

 account of their geological position and relations. 



He then gave a general notice of the topography of many of the 

 islands in the harbor. Their escarpments or precipitous slopes, are 

 on those sides of the islands which face the greatest action of the 

 ocean, while their gentler, grassy slopes are on the protected sides; 

 thus showing the present destructive action of the waves. The 

 specimens wei-e obtained by Mr. G. E. Pierce, a member of the 

 Society, while sinking a well in the centre of Fort Warren. For one 

 hundred feet the excavation was through those loose materials of 

 which the great mass of the islands in the harbor is formed. At this 

 depth there was found a thin bed of indurated argillaceous material, 

 immediately overlying the argillaceous slate of the vicinity of Boston. 

 It was in this bed that well preserved specimens of Nadca heros, 

 Cardita borealis and Venus mercenaria were obtained. From the 

 position in which the shells were found it becomes evident that the 

 specimens were thus imbedded before the deposition of those overlying 

 materials which constitute nearly the whole island. This is equiva- 

 lent to saying, that the species must have existed here before any of 

 the present features of the island were formed, and that they must 

 have survived, not only those changes which were connected with the 

 formation of the island, but also those mutations which have since 

 reversed the action of the waters, and have caused a partial destruc- 

 tion of the islands in the vicinity. 



Mr. W. H. Niles remarked that the recent development of 

 the petroleum interest in our country has disclosed some 

 interesting traces of ancient operations in the "Oil-region" 

 of Pennsylvania. 



With such facts, many persons living in the region, or connected 

 with the oil business, have been familiar, but he thought that they 



