214 Association of Geologists and JValuralists. [Oct., 



Since that occasion, Mr. Redfield has found similar remains in 

 those hills about two miles northward from the first locality, and 

 has collected numerous specimens which he exhibited to the meet- 

 ing, together with samples or fragments of the original beds in- 

 closing these shells, which had been dispersed by the drift and 

 thus lodged in the Brooklyn hills. The number of species com- 

 prised in the collection amounts to ten or twelve, among which 

 are those now most common to our shores. 



These discoveries in regard to the drift appear to agree with 

 those which Sir R. Murchison states to have been made in the 

 drift of Europe. They must be admitted as proving that the 

 most common species of our present mollusks were of prior origin 

 to the hills where the remains were found, and probably older 

 than the entire formation of drift and boulders which is found in 

 the Northern States. The species obtained are not such as indi- 

 cate a colder climate than now^ prevails. But the shells found 

 by Professor Emmons and others in the pleistocene clays on the 

 borders of Lake Champlain, and by Mr. Lyell and others in Can- 

 ada, appears to belong to a later period of the drift, and Mr. Red- 

 field infers that they were brought in from more northern regions, 

 or from deeper waters, by the great arctic currents which must 

 have swept over this region, during the drift period, when this 

 portion of the continent was deeply submerged. These polar 

 currents annually freighted with immense fields and islands of 

 floating ice, such as are now diverted along the shores and banks 

 of Newfoundland, till they are met by the dissolving influence of 

 the Gulf stream, nearly in the latitude of Boston and New York, 

 he considered to have been among the chief agents in producing 

 the remarkable phenomena of the drift period. 



M. Dcsor stated that discoveries in Scandinavia and Northern 

 Europe, that the first deposite of the drift consisting of coarse clay 

 and gravel, and stratified, was of a turbulent character, while the 

 second deposite was a quiet one. Boulders have been brought from 

 the northwest, striccted and scratched all over their surfaces. How 

 much of the phenomena presented upon a close survey of these 

 drifts was attributable to currents of w^ater, M. Desor would leave 

 to others to say. For his own part he believed that these drifts 

 gave evidence of the action of a body different from water. If 

 the drift and boulders were connected in the action, he fully be- 

 lieved that some other agent than water must be looked for to ac- 

 count for their existing. He could not agree with Mr. Redfield 

 in the positions which he had assumed. 



Mr. Redfield was not disposed to look for foreign causes to ac- 

 count for geological phenomena when one of a more domestic 

 character was entirely adequate to produce these phenomena. 



