CONEMAUGH FORMATION OF WESTERN PENNSYLVANIA BASINS 17$ 



Mahoning, from 50 to 70 feet thick, varies somewhat abruptly from mass- 

 ive and coarse, even pebbly, to shaly. Limestones are reported at 70, 

 90, and other distances above the Upper Freeport, but for the most part 

 the intervals as given are merely estimates and the matter is indeterminate 

 throughout. The Gallitzin coal bed seems to be present in Gaskill town- 

 ship, on the Indiana border, where it rests on the "Mahoning," and the 

 coal bed in Young township, the next west, at 138 feet, may he the Brush 

 Creek. * 



The section is still obscure in northern Indiana west from Chestnut 

 ridge. In the central part of the county, 12 miles south from the Jeffer- 

 son line, Mr Piatt finds coal beds at 40, 95, 147, and 177 feet above the 

 Upper Freeport. That at 147 is not far from the place of the Brush 

 Creek, for the lower coals are clearly the Gallitzin beds, as they are* ac- 

 companied by the Upper and Lower Mahoning limestones, the Upper 

 being represented by calcareous ore, which Mr Piatt correlates with the 

 "Johnstown ore" of Cambria county. The "Mahoning" of Jefferson is 

 evidently the Lower Mahoning. Farther southwest, between Blairsville 

 and Chestnut ridge, the whole of the Conemaugh is present. The Pitts- 

 burg limestone and shale, beginning at 20 feet below the coal, are 7 feet 

 thick. A Little Pittsburg coal with its limestone persists at 45 feet, 

 while at 125 feet is a coal and limestone exposure which may be at the 

 Little Clarksburg horizon. Mr Piatt finds a massive sandstone, 40 feet 

 thick, beginning at 145 feet, which he takes to be the Morgantown ; but 

 it is extremely variable, for 2 miles away the interval is occupied by 

 shales containing two red bands 5 and 3 feet, another bed of 7 feet being 

 found at 210. The place of the Ames limestone is concealed in most 

 of the sections reported, but that bed was seen, 3 feet thick, at 9 miles 

 north from Blairsville, where it overlies the thick "Pittsburg reds" and 

 is by barometer 280 feet above the Upper Freeport. The Brush Creek 

 (Black Fossiliferous) limestone was not seen by Mr Piatt and in all 

 probability it is wanting, as the Mahoning is very thick in this corner of 

 the county. If present it should be at about 130 feet below the Ames. 

 The thickness of the Conemaugh as determined from exposures by Mr 

 Piatt is approximately 600 feet, but Mr Richardson gives it as 675 feet 

 in the deep boring at Blairsville.f Mr Piatt thinks the Mahoning at 

 least 150 feet thick east from Blairsville, where an exposure shows 

 LTpper Mahoning massive, somewhat pebbly, and 50 feet thick. The 

 Gallitzin (Philson) coal bed is in three benches and, including 8 feet of 



* W. G. Piatt: (H 6), pp. 21-23, 35, 73-74, 124. 



f G. B. Richardson: U. S. Geol. Survey folios, Indiana (102), 1904. 



