92 FROSTBURG COAL FORMATION. 



ARTICLE IV. 



A descripfAon of the Frosthurg Coal formation of Allegany 

 county^ Maryland^ with an account of its geological position. 

 By Philip T. Tyson. 



[Read before the Academy, Feb. 9, 1837.} 



The centre of this basin is about 115 miles from Baltimore, 

 in a direct line, bearing N. 80° West; its northern limit is 

 near the southern boundary of Pennsylvania, from which it 

 extends south south-westerly, about 525 miles, with a breadth 

 varying between six and seven miles. The Potomac river 

 enters the south-western part of the basin, or rather trough, 

 and flows N. N. E. about six miles, when it receives the 

 Savage river through a gap in Savage mountain, and soon 

 after passes laterally out of the trough through a gap in Dan's 

 mountain. About six miles from the N. N. Eastern limits of 

 the trough, a col or spur crosses it, laterally connecting Dan's 

 and Will's mountains. Three streams take their rise in. 

 this col, near the village of Frosthurg. The largest, called 

 George's creek, flows longitudinally through the trough, and 

 enters the Potomac, about IJ miles in a direct line, below 

 the mouth of the Savage river. Braddock's run flows easterly, 

 through a gap in Dan's mountain, and enters Will's creek 

 about 1§ miles above the town of Cumberland. Jenning's 

 run flows north-east about six miles from Frosthurg, then east 

 through a gap in Dan's mountain, and enters Will's creek 

 about three miles above Cumberland. It will be observed, in 

 the sections, that the coal series is deposited between Dan's and 

 the Savage mountains. The eastern part forms the summit 

 of Dan's mountain, while the Savage is almost entirely com- 

 posed of the coal rocks. The strata dip on every side towards 

 the central parts of the trough, which consequently somewhat 

 resembles in form an American canoe; the inferior limit of 

 the series, is estimated to be from 550 to 600 feet above tide 

 water; the edges of the upper half of the series only, was 

 exposed on the hill sides, within the limits of the lands to 

 which our professional investigations were confined. These 

 embraced the central portions of the trough, within which, a 



