120 Association of American Geologists and Naturalists. 



Dr. Amos Binney read a report " On the influence of physical 

 causes on the distribution of the terrestrial Mollusca of the Uni- 

 ted States and their actual distribution."* 



After Dr. B. had finished his paper on the distribution of the 

 species of Helices in the United States, Mr. Lea objected to the 

 theory of zoological centres to account for certain species being 

 widely distributed. He said that he had no doubt the small 

 species and the young of the larger were carried from one place 

 to another by birds, on whose toes or legs they may have rested 

 when the bird took its flight, and thus be transported by a single 

 effort twenty, fifty, or even one hundred miles. He could see 

 no difficulty in this, 



Mr. Haldeman also made some remarks on this subject, allud- 

 ing to the viev/s advocated in his paper read on Thursday last. 



The meeting adjourned to 8J o'clock. 



Evening session. — Some of the members attended the meet- 

 ing of the National Institute ; after which the Association came 

 to order at 8^ o'clock, Prof. W. R. Johnson in the chair. 



Dr. Locke favored the Association with an exhibition of his 

 striking transparent geological drawings of organic remains and 

 phenomena, following the order of the stratification. 



Dr. Locke then resuming the chair, Mr. W. C. Redfield fol- 

 lowed by reading a paper, in which he noticed some of the phe- 

 nomena of the diluvial period, which had led him to infer that 

 the abrasion of the previously existing rocks, and the transfer 

 and distribution of their detritus, now constituting the great su- 

 perficial formation which is designated as drift, took place during 

 a period of both submersion and subsidence of this portion of the 

 earth's crust. 



He then proceeded to a description of some remarkably abra- 

 ded rocks, having the form of isolated cliff's or island pinnacles, 

 which are found in Rootstown, Portage County, Ohio. These 

 pinnacles exhibit abundant memorials of having been long sub- 

 jected to the lashing of great waves, while partially submersed, 

 at a period which he conceives to have been coeval with, or sub- 

 sequent to, the final distribution and deposit of the drift. These 

 surge-beaten rocks are supposed to be one hundred feet above 



* As Dr. Binney's views are soon to appear in his elaborate volume on the He- 

 lices, now being printed, no abstract is here given. 



