Association of American Geologists and Naturalists. Ill 



tion in their valuable paper, the National Intelligencer— on mo- 

 tion of Mr. Silliman, it was resolved that the thanks of the As- 

 sociation be presented to Messrs. Gales & Seaton, and that their 

 offer be accepted. 



The order of the day was then taken up. Prof. H. D. Ro- 



portion 



Prof. W. 



entitled " A system of classification and nomenclature of the pa- 

 leozoic rocks of the United States, with an account of their dis- 

 tribution more particularly in the Appalachian mountain chain." 



Referring to the great extent of their field operations for the last 

 eight years, which, besides the minute surveys of New Jersey, Penn- 

 sylvania and Virginia, have included a general tracing of the great 

 formations from Lake Huron to Alabama, and for great distances across 

 the chain, they called attention to the ample materials thus collected re- 

 lating to the fossils as well as the mineral character of the formations; 

 from which, and from the data collected by others, they have framed 

 their proposed system of classification and nomenclature. They stated 

 that the great mass of strata composing what they designate as the Ap- 

 aachian system, whose aggregate thickness in some districts exceeds 



■»e? x ^& 



5 UU feet, is made up of an extraordinary number of distinct forma- 

 * , characterized by their organic remains and composition, marking 

 a ong series of events and a vast lapse of time, and constituting one 

 ^interrupted succession of deposits, closely linked by an unbroken 

 cquence of animal and vegetable remains. Viewing the whole as a 

 o e system, the entire record of one continuous period, they propose 

 _ uce from the study of the organic remains of the different portions 

 s mass, aided by considerations of a mineral character, a classifi- 

 cation in harmony with the natural relationship of the different mem- 



nroughout the reman xvh\rh thnv nwrnnv ns to time and circum- 



*wces of origh 



, P and changes in their true relative importance ; and to clothe this 



_ i cation in language which shall at once be suggestive of these re- 



, ** P s > an d applicable every where throughout the vast region of 



Palachian rocks. They showed that in such a system of nomen- 



v l . re w,se ly framed, the primary idea suggested by the terms should 



u of the order in time of the successive formations, and that its 



* ge, comprising in a symmetrical form all the wider as well as more 



C Q groups of strata, and presenting the greater and smaller sub- 



of ^ m ^ Ue su b° r dination, should possess such pliancy as to admit 



hibii^ 1 ^ 810 ^ by SOmo sim P ,e adjunct all the modifications of type ex- 



gio ^ P art *cular divisions of the system in different or distant re- 





