WESTERN COUNTIES OF PENNSYLVANIA 69 



Mr Carll shows that the three sandstones are distinct, with the interven- 

 ing Mercer and Sharon shales. No reference is made to the Mercer lime- 

 stones, but the several coals of the section are present, and evidently as 

 uncertain in occurrence as in the western counties. The sandstones are 

 named Homewood, Connoquenessing, and Garland, the last being the 

 Sharon of White, the Olean of Ashburner.* 



Clarion county, south from Venango, has Jefferson at the east. Doctor 

 Chance's generalized section enables us to recognize here the series as on 

 the Ohio line. It is 



Feet 



Homewood : 30 to 50 



Mercer 35 



Upper Connoquenessing 40 



Quakertown 25 



Lower Connoquenessing and Sharon 130 



The Homewood is often shaly, and the change from a coarse, more or 

 less pebbly, sandstone is often abrupt. It is equally variable in thick- 

 ness, the extremes being 15 and 60 feet. The Mercer group is not shown 

 in detail in the northern part of the county, but the Lower Mercer coal 

 bed is present near Edinburg, and it may be the bed seen at one locality 

 on the eastern side of the county. Both Mercer coals are shown on the 

 Allegheny river in the southern part. The Mercer limestones are absent, 

 but in the extreme southeast an ore bed was seen near the place of the 

 lower bed. The Upper Connoquenessing sandstone is distinct through- 

 out, separated by 4 to 35 feet of Quakertown shales from the lower sand- 

 stone, which in the central part of the county is continuous with the 

 Sharon sandstone ; but the Sharon shales, 45 feet thick, are present in 

 the southeast corner of the county, where the sandstones are 50 and 40 

 feet respectively. The Quakertown and Sharon coal beds are unrepre- 

 sented, f 



Butler county is south from Venango and east from Mercer and 

 Lawrence. 



The Homewood sandstone is shown occasionally in the northern part 

 of the county as a coarse, iron-stained sandstone at least 30 feet thick. 

 It is thinner along the Mercer and Lawrence line, varying from 15 to 30 

 feet, but is thicker in the central portion, while on the eastern side, ad- 

 joining Armstrong county, it is from 15 to 80 feet, varying at the expense 

 of the Mercer shales. 



The ' ; Tionesta coal bed " is present on the west side, adjoining Law- 

 rence, where it underlies the Homewood and is 2 feet thick, but it was 



* J. F. Carll : Geology of the Oil Regions (I 3), 1880, p. 14. 



tH. M. Chance: Geology of Clarion County (V 2), 1880, pp. 73, 106, 116, 123, 134, 147, 162, 164, 177. 

 X— Bull. Geol. Soc. Am., Vol. 15, 1903 



