Report of the Curator. 7 



the State, and part of tlieiii have been arranged and ticketed 

 with the localities from wliicli they were derived. 



From the Hamilton group, in southeastern New York. Mr. J. 

 W. Hall and George B. Simpson have collected six large boxes 

 of specimens. These collections have been examined, ticketed 

 and recorded. They prove to be mostly Lamellibranchiate 

 shells, which were very much needed in xthe collections for 

 study, and they have also added largely to the means of 

 placing the fossils of this class in the duplicate collections for 

 distribution, for which we have not heretofore had the materials. 



Aside from the importance and necessity of possessing these 

 collections for study, it has become very important to deter- 

 mine the limits of the geological formations to which the New 

 York geologists have given names. The nomenclature was, 

 after all the investigations, a compromise among those occuijied 

 in the work ; for at that time no individual of the four persons 

 engaged had traced these formations continuously from the 

 eastern to the western extremity of the State. 



We have long possessed evidence to show that the recognition 

 of certain of the formations in some of the southern and south- 

 eastern counties had been based upon incorrect or insufficient 

 information. The almost total absence of fossils from the higher 

 strata in the eastern part of the State, and the coming in of red 

 rock in the formation above the Hamilton group, had induced 

 Mr. Mather to recognize the great accumulation of strata form- 

 ing the Catskill Mountains, as the "Catskill group." Mr. 

 Yanuxem, with a true knowledge of the succession in the 

 central part of the State, nevertheless yielded to Mr. Mather s 

 views in the more difficult and inaccessible portions of the 

 countr}^ bordering the two districts, and the name "Catskill" 

 superseded the "Montrose and Oneonta sandstone" of the 

 Annual Reports. In conformity with this view, the geological 

 maj) has been made to represent a thinning of the Chemung 

 group in the eastern part of the State, without any recognition 

 of the existence of the Portage grouj) in that region. This 

 discrepancy between the nomenclature, as recognized in the 

 central and western parts of the State, and that of the south- 

 eastern counties, I had observed as early as the year 1844, while 

 engaged in the collection of materials for the Palaeontology of 

 New Y^ork. 



The adoption of Mr. Mather s views left little place for the 

 Chemung group, and it was onl}-^ by recognizing the higher 



