138 Prof. Johnson's Repert on the Bradford Coal Field. 



valley of Towanda creek. On this creek itself, the lower beds 

 of limestones, sandstones and shales underlying the coal measures 

 are found at a high angle of inclination, often dipping not less 

 than 40° or 50° towards the south or southeast. On the easterly 

 and southeasterly parts of the coal field, on the contrary, the dip 

 of the lower rocks is to the west or northwest, while on the 

 southwestern parts, especially on Burnet ridge, the slope is evi- 

 dently towards the north. " The coal measures He on both sides 

 of the Carbon creek, the valley of which, as well as those of its 

 tributaries, is a valley of denudation, made by the action of water, 

 which at the northeastern extremity of the coal basin has exca- 

 vated its channel through the whole coal series, over two hun- 

 dred feet thick, and to a depth of more than seven hundred and 

 fifty feet below them, into the underlying strata of slates, lime- 

 stones, sandstones and shales. 



Great pains appears to have been bestowed by Prof. Johnson, 

 in determining by actual survey and levelling, the true elevation 

 of all the important points where any of the mineral deposits are 

 opened. This was rendered necessary as well by the wilderness 

 and uncultivated condition of the country which prevented ex- 

 tended observation as by the generally level position of the strata 

 which rendered it often difficult to determine the dip in the ordi- 

 nary manner. 



It appears that the main beds of coal in the Bradford district 

 are two, one of from five to seven feet and the other from thirty 

 inches to three feet in thickness with some intermediate plies of 

 less value. They lie about one thousand one hundred and twelve 

 feet and one thousand two hundred and nineteen feet respectively 

 above the level of the Susquehanna river at Towanda, distant 

 from ten to fourteen miles. The mineral deposits constitute the 

 upper portions, in the nature of outlying masses of the formation, 

 and all the streams which intersect the coal field are found in so 

 many valleys of denudation, which being wider above than below, 

 have of necessity, destroyed more of the upper than of the lower 

 beds of coal. This coal field, like nearly all others whether in 

 this country or elsewhere, abounds in the argillaceous carbonate 

 of iron and in seams of fire clay. Calcareous conglomerates are 

 likewise seen at different elevations, but no considerable body of 

 good limestone has yet been developed immediately within the 

 coal field. "^ 



