Charles Schuchert — Historical Geology, 1818-1918. 69 



Permian period. 



Upper Barren series. 

 Dunkard group. 

 Washington group. 

 Pennsylvanian period. 



Upper Productive Coal series. Monongahela series. 

 Lower Barren Coal Measures. Conemaugh series. 

 Lower Productive Coal Measures. Allegheny series. 

 Pottsville series. 



The New York System. — We now come to the epochal 

 survey of the State of New York, one that established 

 the principles of, and put order into, American strati- 

 graphy from the Upper Cambrian to the top of the 

 Devonian. No better area could have been selected for 

 the establishing of this sequence. This survey also 

 developed a stratigraphic nomenclature based on New 

 York localities and rock exposures, and made full use of 

 the entombed fossils in correlation. Incidentally it devel- 

 oped and brought into prominence James Hall, who con- 

 tinued the stratigraphic work so well begun and who 

 also laid the foundation for paleontology in America, 

 becoming its leading invertebrate worker. 



This work is reviewed at great length in the Journal 

 in the volumes for 1844-1847 by D. D. Owen. Evidently 

 it followed too new a plan to receive fulsome praise from 

 conservative Owen, as it should have. He remarks that 

 the volumes ' ' are not a little prolix, are voluminous and 

 expensive, and do not give as clear and connected a view 

 of the geological features of the state as could be wished. 

 . . . We are of the opinion that before this work can 

 become generally useful and extensively circulated, it 

 must be condensed and arranged into one compendious 

 volume" (46, 144, 1844). This was never done and yet 

 the work was everywhere accepted at once, and to this 

 end undoubtedly Owen's detailed review helped much. 



The Natural History Survey of New York was organ- 

 ized in 1836 and completed in 1843. The state was 

 divided into four districts, and to these were finally 

 assigned the following experienced geologists. The 

 southeastern part was named the First District, with W. 

 W. Mather (1804-1859) as geologist; the northeastern 

 quarter was the Second District, with Ebenezer Emmons 

 (1799-1863) in charge; the central portion was the Third 

 District, under Lardner Vanuxem (1792-1848) ; while 



