CHAPTER II. 



THE GENERAL APPLICATION OF THE NOMENCLATURE OF THE 

 NEW YORK SYSTEM AS A STANDARD OF CORRELATION IN 



OTHER PARTS OF THE UNITED STATES. 1840 TO 1851. 



• 



The termination of the New York State Survey and the publication 

 of the final reports practically established the new ideals for the classi- 

 fication of the Paleozoic rocks of North America. 



The Final Report on the Geology of the Fourth District (the western 

 quarter of the State) by James Hall was published in 1843. This may 

 be regarded as expressing the more perfected views in regard to classi- 

 fication and nomenclature. 



The New York system was the comprehensive term applied to the 

 series of rocks beginning with the Potsdam sandstone and terminating 

 in the " Chemung group." The rocks of the Catskill Stage were called 

 the Old Red system or Old Red sandstone. The New York system 

 was made up of twenty-nine " systematic subdivisions," "founded upon 

 the fossil and lithological characters." 1 



These were grouped into four " geographical subdivisions." The 

 lowest, from the Potsdam to the Oneida Conglomerate, inclusive, was 

 named the il Champlain Division ; " the second, including the Medina, 

 the Clinton, and the Niagara, was called the u Ontario Division." From 

 the Onondaga Salt group to the Corniferous limestone, inclusive,was the 

 u Helderberg series." From the Marcellus to the Chemung, inclusive, 

 was the " Erie Division." 



Comparisons had been made with the Silurian system of Murchison 

 and the Devonian of Murchi son and Phillips, and a general corre- 

 lation recognized, but the equivalencies were not minutely accordant. 



In respect of the part of the scale with which this essay is con- 

 cerned, the author wrote, " If the Devonian is to be regarded as a dis- 

 tinct system, we shall find its repesentatives in the Chemung and Port- 

 age groups, with perhaps a part of the Hamilton group. In New York, 

 however, as already stated, no subdivisions can be made which are 

 entitled to the name of systems." 2 



1 (No. 3 of p. 18 was expanded into two sub divisions on p. 517 (i. e., Nos. 27, 26) by the recognition of 

 the Chazy limestoneas distinct from the Black River limestone.) 



2 Geology of New York, part iv. comprising tbe survey of the fourtb geological district, by James 

 Hall, 1843, p. 516, 



58 



