116 THE DEVONIAN AND CARBONIFEROUS. Ibull.80. 



State studied by hiin. 1 He correlated it with the Olean Conglomerate 

 of McKean County, the Sharon Conglomerate of Mercer County, the 

 Ohio Conglomerate of Ohio, and the Second Mountain sand of the oil 

 wells. 



" Sub-Garland sandstone " was used for Mr. Ashburner's " Sub olean" 

 and Mr. White's " Shenango sandstone." In chapter vi the author, by 

 the application of the methods of correlation suggested by his experi- 

 ence with oil well records, determined the Panama Conglomerate of 

 Chautauqua County, New York, first, to be older than the Olean or 

 Garland Conglomerate; second, to be neither of the Venango oil sands; 

 and third, to be of Chemung age by lying below the horizon of the Ve- 

 nango oil sand group. 2 



lie pointed out the important distinction that the pebbles of the Pan- 

 ama Conglomerates are almost always lentiform or flat in shape, while 

 the pebbles of the higher Carboniferous Conglomerates are irregularly 

 spheroidal. 3 



By the same methods he argued that the place of the Salamanca Con- 

 glomerate is above the Panama Conglomerate. 4 Again, he correlated 

 the " First Mountain sand " with the Conoquenessing sandstone of 

 Butler County and the Kinzua Creek sandstone of McKean County; 

 the " Second Mountain sand" is a synonym for the Garland Conglom- 

 erate; for the "Third Mountain sand" of the earlier reports of the 

 oil men, he proposed the name " Pithole grit," which he considered 

 equivalent to the Berea grit of Ohio. 6 



The author prepared the following generalized section of the formation 

 from the Upper Barren Coal series of Greene County, Pennsylvania, 

 down to the Corniferous limestone, which will show his interpretation 

 of the series as the result of a detailed study of oil well records : 6 



Feet. 

 ( Upper Barren Coal Measures, B. 



j Greene County group, from top to Washington upper limestone... 600 



) Upper Barren Coal Measures, A. 



Wasbiugton County group, extending to Waynesburg sandstone.. 350 



2. Upper Productive Coal Measures, to base of Pittsburg coal 475 



3. Lower Barren Coal Measures, to top of Mahoning sandstone 500 



4. Lower Productive Coal Measures, to top of Conglomerate No. XII 400 



5. Mountain Sand series, to base of Olean-Garland-Obio Conglomerate ^375 



6. Crawford sb ales, to top of Venango Oil group =p450 



7. Venango Oil group, from top of "First Oil Sand" to bottom of the 



"Third Oil Sand" ^350 



8. Interval between the Venango Oil group and the Warren Oil group ±300 



9. Warren Oil group ....• 300 



10. Interval v 400 



11. " Bradford Third Sand" 20 to 80 



12. Interval between the Bradford u Third Sand " and the Corniferous lime 



stone, commencing in the Chemung and including the Portage and 

 Hamilton groups of the New York Geological Survey 1,600 



13. Corniferous limestone 



1 Ropt. of Trogress, I 3 , p. 13. 2 Ibid., p. 77. 3 Ibid., p. 60. "Ibid., p. 79. 



6 Ibid., p. 82, and cbapter 8, p. 91. 6 Kept, of Progress, III, pp. 156-164. 



