1892. J PROSSER THE GENESEE SECTION. 65 



If Professor Williams' correlation of the Richburgh oil sand with 

 the Portage sandstone be correct, then the fossils in the gas sand of 

 the wells on lot No. 2 prove that they did not reach the Richburgh 

 sand. 



On the other side, assuming that the elevation of the mouth of 

 well No. 91 is 2300' A. T., and comparing the elevation of the top of 

 the oil sand above sea level with that of the Richburgh wells, we find 

 that there is not much difference. The top of the oil sand in well No. 

 91 is about 880' A. T., and Professor Williams states that the average 

 altitude of the top of the Richburgh oil sand in nine of the Varney & 

 Co. wells " is 800 feet above the sea, or something over a thousand 

 feet below the flat pebble conglomerate of the Upper Chemung." (') 

 Professor Williams also makes the distance from the base of the 

 Olean conglomerate to the top of the Richburgh oil sand about the 

 same as in well No. gi. The top of the flat pebble conglomerate is 

 given as 1875', which is based on the supposition that the R. R. station 

 at Bolivar is 1600'. Since the station is 1625', then the top of the con- 

 glomerate would be 1900' A. T. 1900' — 800' (top of oil sand in wells) 

 =■ 1 100' for the distance from the flat pebble conglomerate to the top 

 of the oil sand. 1100' + 300' (average distance between the conglo- 

 merates) = 1400' for the distance from the base of the Olean con- 

 glomerate to the top of the Richburgh oil sand. 



Since well No. 91 is not much farther north than the Varney & 

 Co. wells, the above statements seem to show that well No. 91 did 

 reach the Richburgh oil sand ; that this sand, or at most only ^;^' 

 above it, is fossiliferous containing Chemung species and conse- 

 quently that the Richburgh sand is in the Chemung. If this corre- 

 lation be correct then the Richburgh oil sand is above the Portage 

 sandstones and Ashburner was correct in referring the Allegany oil 

 sandstones to the Chemung. ('■) 



It appears to the writer that the explanation of the confusing 

 views on the stratigraphical geology of southwestern New York and 

 northwestern Pennsylvania is due in great measure to the belief of 

 some geologists in the "persistent parallelism of strata " for consider- 

 able distances. While, as a matter of fact, it is probable that the lith- 



(I.) Ibid.y p. go. 



(2.) 2d Geol. Surv. Pa. R, 18S0, in the " vertical section of the rocks of McKean Co.," on p. 

 43 the Bradford oil sand is given as middle Chemung. And in the Trans. Am. Inst. Min. Eng., 

 vol. .\vi, pp. 927, 929, the Richburgh oil sand is positively correlated with the Bradford oil sand by 

 Ashburner. 



5, Pkoc. Roch. Acad, of Sc, Vol. 2, May, 1892. 



