202 NEW YORK STATE MUSEUM 



The Becraft is a coarsely crystalline limestone (calcarenite) in 

 sections i, 2 and 3, containing many specimens of G y p i d u 1 a 

 pseudog'aleata ( Hall) and Spirifer concinnus 

 Hall. In section 4 these beds will probably be found in the lower 

 portion of the covered strata called Port Ewen, as the upper 20 feet of 

 that section, correlated with the Becraft on stratigraphic grounds, 

 are very similar both lithically and faunally to the uppermost New 

 Scotland of section 3. No Gypidula pseudogaleata 

 occurs in the Maryland section but Spirifer concinnus 

 does ; the latter species is thus found in all the sections, omitting 

 section 4. Spirifer macropleura (Conrad) does not 

 occur in the Becraft in any section. 



The Port Ewen is not recognized in section 5, and is covered in 

 section 4. In section i it is very similar lithically and faunally to 

 the Coeymans, while in sections 2 and 3 it quite closely resembles in 

 like characters the New Scotland. 



The Oriskany of all the sections is more or less silicious. Some 

 beds of section 2 and the upper Oriskany of section 5 are more dis- 

 tinctly sandstones. The fauna of sections i and 2 and the upper 

 ^ds of 3 and 4 represent the calcareous facies of the normal Oris- 

 l<any.^ Sections i and 2 contain many more of the typical shallow 

 ^ater forms than do sections 3 and 4. The lower beds of sections 3, 

 4 and 5 contain an older Oriskany fauna. In the shallowing waters 

 of the upper portion of the Oriskany of section 5 there was devel- 

 oped the normal Oriskany fauna. 



As seen from the above sections, there is an increase in thickness 

 of the upper Siluric and the lower Devonic strata from the north to 

 the south, indicating a greater subsidence in the latter than in the 

 former regions. These strata thin out westward in New York State, 

 disappearing, with the exception of 7 feet of Manlius^ and several 

 inches of doul)tful Oriskany sandstone, before Buffalo is reached. 

 This is shown in the accompanying diagram [fig.4] taken from 

 Hartnagel's report on the Cobleskill limestone of New York.^ 



^See Oriskany under "General description of each horizon." 

 ^Grabau, A. W. Siluro-Devonic Contact in N. Y. Geol. Soc. Am. Bui. 

 1900. p.347-76. 



^Hartnagel, C. A. Preliminary Observations on the Cobleskill (" Coral- 

 line") Limestone of New York. N. Y. State Paleontol. An. Rep't. 1902. 

 p.i 109-75. 



