58 



means of ascertaining the value of particular parts of the formation. 

 For it must be plain that the ordinary mode of mining, applicable to 

 other coal fields, may be ruinously fallacious when applied to this. 

 The intricacy of the faults, and the changing thickness of the coal, 

 are features calculated to baffle and defy the anticipations of the 

 miner. A profound knowledge of the nature and extent of the local 

 disturbances around him, together with some general rules appli- 

 cable to all coal mines, may enable him to approximate with con- 

 siderable accuracy to the depth and position at which he is to meet 

 the coal seam, but he can form little or no anticipation from knowing 

 its thickness elsewhere, what its thickness will be when he reaches 

 it in the new place. In most coal fields he may. The reason of the 

 difference is, that in the present case the coal lies almost immedi- 

 ately contiguous to the undulating surface of the primary rocks be- 

 low, and must partake, especially in its lower surface, of the plain 

 upon which it was deposited. In most other coal regions the un- 

 derlying rocks are either sandstones, limestones or slates, themselves 

 originally horizontal deposites furnishing a level floor upon which 

 the carboniferous matter would necessarily spread itself in an even 

 sheet. 



What is here said is not intended to throw a damp upon enter- 

 prise which is pursuing the developement of this coal field; on the 

 other hand, we regard it as one of the most valuable deposites of 

 mineral wealth within the area of Virginia. Our duty is by practi- 

 cal suggestions derived from the best sources within our reach, to 

 promote a sound direction to the enterprise and capital employed 

 upon the mineral resources of the state — to teach caution where ne- 

 cessary, but not to discourage. 



The fine qualities of the coal in this coal field, both for domestic 

 uses and manufacturing purposes, together with the very enormous 

 thickness of the deposite in many of the mines where it is pursued, 

 hold out an ample guarantee, that if prosecuted upon a correct con- 

 ception of its internal structure, it must always prove a profitable 

 region to the quarter of the state in which it lies. 



There is one suggestion which we venture strenuously to enforce 

 — the great importance of preserving specimens of the various 

 layers of rock penetrated by the shafts which are sunk from time to 

 time, or in any borings that may be made. The rocks resting above 

 the coal are less liable to be affected by local variations than the 

 coal itself, for reasons previously explained — and most important 



