FROSTBURG COAL FORMATION. 93 



topographical survey was made, under the direction of my 

 colleague, J, H. Alexander, Esq. over a tract of country 

 embracing more than twenty square miles. The streams 

 before noticed, with their numerous tributaries, have formed 

 ravines to such an extent, as to have removed perhaps two- 

 thirds of the contents of the beds as they once existed ; they 

 have however compensated for the waste, in furnishing 

 facilities for the investigation and extraction of the valuable 

 materials, without the expenses attendant upon deep mining 

 and pumping; for the whole quantity of coal and iron ore at 

 present known, amounting to about sixty feet of the former, 

 and more than ten of the latter, may be extracted without the 

 use of a shaft, and consequently without having to lift the 

 water. 



George's creek, in its passage from Frostburg, cuts through 

 beds of the series, whose aggregate thickness is about 1300 

 feet, and nearly reaches the inferior hmits. The Potomac has 

 carried off nearly the whole of the principal beds of coal in 

 the part of the trough through which it flows; the main coal 

 or fourteen feet bed being 8 or 900 feet above the river, and is 

 only found in small areas in the few hill tops, or spurs from 

 the mountains on either side, which preserve that elevation. 

 Jenning's run descends 100 feet to the mile, and as the strata 

 rise considerably in the direction of its course, it cuts through 

 the whole series within a few miles of its source. Braddock's 

 run has carried off but a small portion, because it flows 

 laterally, and soon runs out of the basin. 



In order to assist in ascertaining the structure of the region 

 and its contents, sections were excavated on divers hill sides, 

 and the position of the beds determined by levellings and 

 measurements. One of these is selected, as the best calcu- 

 lated to illustrate the character of the region. The position is 

 about the centre of the formation on the south-eastern slope 

 of Dug hill, a spur of the Savage mountain. The hill rises 

 abruptly about 550 feet in elevation from the bed of George's 

 creek, and then slopes off gradually 150 feet more. The 

 surface of this last portion, is covered by detached fragments 

 of coarse grit and sandstone, and no excavations were made 

 into the strata thus covered ; but in descending, we first find 



