PORTION OF THE SCHUYLKILL COAL-FIELD. 91 



mains to be added here, under this head, will occupy a brief 

 space.* 



Ranging along the southern margin of this coal-field, appear 

 nine principal transverse sections, " gaps " as they are locally 

 termed, which cut through Sharp mountain. Through these ra- 

 vines, many hundred feet in depth, the drainage of the coal area 

 descends southward ; and by the same avenues the higlily inclined 

 coal seams are intersected. The height at which these coal seams 

 can now be reached within the gaps, without expensive tunnel- 

 ling, varies from eight hundred to eleven hundred feet above the 

 level of the sea ; and as the summit attains an elevation of six- 

 teen hundred and fifty feet, there are therefore from four hundred 

 to eight hundred and fifty feet, measuring perpendicularly, of coal, 

 capable of being worked, above those points of intersection. 



The number, thickness, compactness and density of these coal 

 seams increase as we pass eastward along the counties of Dau- 

 phin, Lebanon and Schuylkill. At the same time, and in a cor- 

 responding degree, or rather in a reverse ratio, the amount of bitu- 

 minous and volatile matter, contained within the coal, diminishes ; 

 passing from a bituminous or semi-bituminous coal, which yields 

 a bright blazing fire, and at some points is convertible into coke of 

 good quality, to a compact anthracite, on the borders of Schuyl- 

 kill county. This fact is exemplified in the series of analyses 

 made on behalf of the proprietors and published in 1840, and sub- 

 sequently by another series, recently embodied in the State geo- 

 logical report. The prevailing breadth of this southern fork, 

 measuring from red shale to red shale, is about a mile ; except 

 towards the western termination, where it is only about one thou- 

 sand feet to one thousand and two hundred feet wide, for three 

 or four miles. In this range, the lower conglomerate, interposed 

 in gi'eat thickness towards the eastern exti'emity of the Schuyl- 

 Idll coal basin, between the coal beds and the red shale, has thin- 

 ned out and at some points appears to be altogether absent. The 



* At the request of the-author, we have, in printing the memoir, omitted many details 

 which were embodied in the original ; because without the assistance of maps and dia- 

 grams, they could not be rendered sutRciently intelligible to the reader. 



