New York State Education Department 



New York State Museum 



John M. Clarke Director 



Bulletin 81 

 PALEONTOLOGY 1 1 



GEOLOGY 



OF TTIE 



WATKINS AND ELMIRA QUADRANGLES 



ACCOMPANIED PY A GEOLOGIC MAP 

 BY JOHN M. CLARKE AND I). DANA LUTHER 



The detailed mapping of this area has been carried out as a con- 

 tinuation of the work beginning farther to the west and will be found 

 to be a pictorial representation of the upper series of the formations 

 likewise shown in detail on the Canandaigua-Naples sheet which 

 has but recently been issued. The field traverses for this map have 

 been made by D. Dana Luther, in which he has had the help, as field 

 assistant, of H. S. Mattimore. An interval remains between the 

 area here presented and that covered by the Canandaigua-Naples 

 sheet and this is now in process of survey and will be ready for pub- 

 lication in the near future. The large scale of these maps has per- 

 mitted the delineation of the variations in the formations with very 

 great exactitude and the basis of discrimination for these refined 

 subdivisions has been both a lithologic and a paleontologic one. 



Experience lias taught us that, in this work, which now requires 

 patient effort and precise methods, a reliable basis of classification 

 can be found in neither of these elements alone and in this entire 

 series of maps we have employed the two standards referred to. In 

 the determination of the stratigraphic distinctions here represented 

 pertaining to the late Devonic, obscurities and perplexities increase 

 from Canandaigua lake eastward and they have therefore, on the map 

 now presented, been treated with the utmost caution. 



