Association of Americmi Geologists and Naturalists. 173 



As going to show the inchned position of the strata at the time 

 when these impressions were made, Prof. W. B. Rogers called 

 attention to a peculiarity in the form of many of these impres- 

 sions, noticed by himself and Prof. H. D. Rogers in company 

 with Prof. Hitchcock, during the last summer, and often remark- 

 ed by Prof. Hitchcock on previous occasions. The feature refer- 

 red to resembles the effect of a slight sliding of the foot in soft 

 clay. It is seen in some of the larger footsteps, both those which 

 point upwards and downwards in reference to the present slope 

 of the rocks, and is even more conspicuous vfhere the animal has 

 been walking horizontally along the inclined surface, in which 

 case there is a protuberance on the downhill side of each impres- 

 sion, as if in virtue of the slope the pressure of the foot had ac- 

 cumulated the soft clay in that direction. Adjourned to 



Thursday^ 3 J o'clock, P. M. — Prof. W. B. Rogers in the chair. 

 A communication from Prof Chester Dewey on the polished 

 rocks of Rochester, N. Y. 



Dr. Locke exhibited about eighty colored casts of the fossils 

 found in the western rocks, with explanatory remarks, and upon 

 the advantages to be derived to geological science from the dis- 

 tribution of similar copies. 



JSIr. James Hall and Prof. H. D. Rogers offered some re- 

 marks on observations made in connection with Dr. Locke on 

 the same subject. 



Dr. King expressed the opinion that the fossils exhibited by 

 Dr. Locke, were not generally the same as those common to the 

 lead-bearing series of the upper Mississippi, and that from his in- 

 vestigations, which had been pretty extensive, he believed that 

 the portion of the formation of that region in which the lead is 

 found, overlies, and is very distinct fron^what is considered by 

 Dr. Locke to be the cliff formation of Ohio. To this Prof Locke 

 replied that the fossils presented by him, were not presented as 

 the fossils of that part of the cliff limestone, containing the lead 

 ore ; some of them were actually from the stratum overlying that 

 ore. 



Resolved, That the attention of the meeting be strictly confin- 

 ed to the reading of papers, during the remainder of the present 

 session, and that no discussion be allowed thereon. 



Mr. James Hall read a paper in connection with a section 

 which he exhibited, of the rocks extending from Cleveland, Ohio, 

 southwesterly to the Mississippi. 



