WILLIAM8.] CARLL, CHANCE. 117 



Mr. Carll further discussed the Conglomerates in his report on War- 

 ren County. 1 



The Pottsville Conglomerate No. 12 was subdivided into upper, mid- 

 dle, and lower beds, called " Johnson's Run rocks," " Kinzua Creek sand- 

 stone," and " Olean Conglomerate." 



He correlated these with u Homewood sandstone," "Conoquenessing 

 sandstone," and "Sharon Conglomerate" of the reports Q, Q 2 , Q 3 , and 

 Q 4 . And he proposed to drop the name ^Garland Conglomerate " as a 

 synonym for the Olean Conglomerate of Mr. Ashburuer ? s report on 

 McKean County. 2 



In the chapter on the Panama Conglomerate Mr. Carll defended his 

 former opinion that the Panama Conglomerate is not equivalent to any 

 member of the Venango group but stratigraphically is below it, against 

 the view published by Mr. White in Q 4 , that the Panama represents 

 the Third oil sand of the Venango oil group. Mr. White claimed the 

 equivalency upon evidence of fossils. Mr. Carll objected to the recog- 

 nition of the Venango group as Chemung, on account of the absence of 

 any Chemung fossils in any of the members of that group as seen in 

 the Venango County sections. 3 Mr. Carll's method was based upon 

 the theory of the persistent parallelism of strata. While for short dis- 

 tances and in certain directions no doubt the dominant character of the 

 strata could be traced, often this theory utterly failed him, as he con- 

 fessed in a foot-note on page 205, where, discussing the relations of 

 the sub-Olean and Salamanca Conglomerate across Warren County, 

 he says : 4 



Sometimes no trace of the particular sand rock sought for could be found in proper 

 place, and instead of it other massive pebbly strata would obtrude themselves, 100 

 feet too high or 100 feet too low to fit into the [places where, according to our theory 

 of persistent parallelism of strata, they ought to belong. 



In report V 5 Mr. Chance discusses the u geology of northern Butler 

 and parts of Beaver, Lawrence, and Mercer Counties." Aside from the 

 detailed geology the most important contribution toward the develop- 

 ment of the classification of the Pennsylvania rocks was his analysis of 

 the Coal Measure Conglomerate, No. XII. Tbe following table exhib- 

 its it: 6 



f Homewood Sandstone. 

 I !LVI©rcpr otoud coils 

 Coal Measure Conglomerate, No. XII. ' Cono * easing group, sandstone. 

 =Beaver Kiver series. ^ Sharo 1 u group> g oal and shales> 



l^Ohio Conglomerate. 



1 Kept, of Progress I 4 , 1883. 



'Ibid., p. 185. 



"Ibid., p. 195, et seq. 



4 Ibid., p. 205, foot-note. 



6 Geol. Survey of Pennsylvania, Report of Progress V. Report on northern Butler County; and 

 (Part 2) special report on the Beaver and Sbenango River Coal Measures, by H. M. Chance, 1879, 

 pp. 248. 



•Ibid., p. 188. 



