Maryland Geological Survey 



343 



sandstones " are overlaid by a considerable mass of flags and sands which 

 continue to carry a N"aples fauna with some modifications, but embrace 

 no typical Chemung species." ' This upper zone carrying a Naples fauna 

 and overlying the Portage sandstone is the one noted in 1840 by Professor 

 Hall in the Genesee Valley to which in a section of this valley Dr. Clarke 

 gave the name " Wiscoy shales and flags." ' In the succeeding report 

 appeared an extended account of " The Naples fauna (fauna with Manti- 

 coccras intumescens) in western New York " in which Dr. Clarke gave a 

 history of the Portage group and this fauna.^ 



Later and more detailed stratigraphic work by Dr. J. M. Clarke and 

 Mr. D. Dana Luther in western New York has resulted in a greater sub- 

 division of the Upper Devonian rocks. A recent publication devoted to 

 this subject is their " Geologic map of the Canandaigua and Naples quad- 

 rangles" on which the several formations of these two quadrangles are 

 very accurately represented. The rock formations represented as units 

 of sedimentation " are given in the right-hand column of the follo'wing 

 table, divisions of broader value constituting the other three columns : 



f Prattsburg. 



tHighpoint. 



Neodevomc. 



ChautauQuan group. .Chemung beds. 



Senecan group. 



Ithaca beds. 



Portage beds. 



/West hill. 

 iGrimes. 



Hatch. 



Rhinestreet. 



Cashaqua, 



Parrish (lentil in 



Cashaqua). 

 Middlesex. 



{Standish. 

 West river. 

 Genundewa. 

 ~ Genesee. 



Tully limestone Tully." * 



' 15th An. Rep. State Geologist [N. Y.], p. 58. 



"Ibid., -p. 62. 



neth An. Rep. State Geologist [N. Y.], 1899 [April, 1900], p. 41. Reprint 

 issued in 1898. 



* N. Y. State Museum, Geologic map of the Canandaigua and Naples quad- 

 rangles, April, 1904, p. 2. For descriptions of the above formations, see pp. 

 18-32. 



