REPORT OF THE STATE PALEONTOLOGIST 1900 7 



south through the Chemung rocks of the state at about the merid- 

 ian of the Genesee valley. The heavy mass of these strata, which 

 comprises nearly the entire rock beds of the southern tier of coun- 

 ties, has never yet been satisfactorily subdivided either on the 

 basis of the lithologic differences in its beds or of the variations 

 in its fossil faunas, nor have all the investigations of past years 

 determined with any degree of security the plane of its upper 

 boundary, which is also the line of demarkation between the 

 Devonic and Carbonic systems. In the work of previous seasons 

 the section of the immediately underlying Portage series along 

 this meridian and in neighboring regions east and west, had been 

 carefully review^ed with the purpose of acquiring a more detailed 

 knowledge of it«s stratigraphic and paleontologic relations to the 

 Chemung formation. D. D. Luther made the traverse referred 

 to late in the autumn of last year and rendered a concise report 

 thereon. The result of this reconnaissance was* sufficient to in- 

 dicate the great importance to the accuracy of our geologic map« 

 of the mnch more detailed survey of the region covered by these 

 beds. I am therefore pleased to be able to report that in the 

 ^execution of work planned for the season of 1900 it has been pos- 

 sible to acquire results of positive value bearing on the solution 

 of this problem. To these investigations farther reference will 

 he made. 



Sections of the Oriskany formation. In completion of some work 

 which had continued in a desultory way during the tw-o preceding 

 seasons, Mr Luther was also engaged for a short time in the 

 autumn and early winter in bringing together and correlating 

 the sections of the Oriskany formation throughout central and 

 western New York. These investigations, taken in connection 

 with the writer's more protracted .study of the Oriskany in east- 

 ern and southeastern New York, have afforded the data for a 

 somewhat modified conception of the physical characteristics 

 and the organic traits of this period of geologic time. 



With the opening of the field season of the present year the 

 following lines of work were undertaken. 



