293 



After some general conversation upon the subjects of the 

 paper, the Institute took a recess and then adjourned. 



May 28, 1861. 



The president, Mr. Pruyn, presided. 

 Donations announced : 



Proceedings of American Antiquarian Society. 

 Proceedings of Essex Institute. 



Prof. Hall then proceeded to present his communication 

 on Geology, especially with reference to the proof of the 

 existence of aTaconic system of rocks. He explained by what 

 evidence the succession of strata in rocks, first, the superpo- 

 sition of strata would actually be observed ; then the fos- 

 sils belonging to each determined. When the fossils have 

 thus been thoroughly ascertained, as they have been now, 

 they serve afterwards as the most satisfactory evidence of 

 the relative age of rocks in any disputed locality. 



Prof. Hall then discussed the number and character of 

 the fossils found, especially of trilobites, in the successive 

 eras of rock, exhibiting a chart in illustration of his posi- 

 tion, showing the extent and range of the different kinds of 

 trilobites. From arguments founded on these facts, Prof. 

 Hall contended there was no ground for the position held 

 by those who advocate the Taconic theory. 



At the close of Prof. Hall's communication, the Institute 

 took a recess, after which they adjourned to the last Tues- 

 day of October. 



November 19, 1861. 

 The president, Mr. Pruyn, presided. 



The following donations were announced : 

 Historical Collections of the Essex Institute. 

 Proceedings of Boston Society of Natural History. 

 40th Annual Report of New York Mercantile Library 

 Association, 1861. 



Memoirs of Royal Society of Konigsberg, 1860. 

 [Trans, iv.] 39 



