53 



group is characterised by containing coal to a greater or less 

 amount throughout its whole extent, is yet a question, and one 

 which can only be determined after minute and elaborate investi- 

 gation. Traces of good bituminous coal are detected at intervals 

 over a space of nearly 35 miles in length, from the South Anna 

 near its mouth to near the Appomattox river ; but there is nothing 

 to assure us that the sandstone in which the coal occurs, does not 

 range, at least in some directions, beyond the limits where the coal 

 itself thins away and disappears. Towards the central part of the 

 formation, — namely, within a few miles on either side of James 

 river, — the coal appears to be thickest ; and it is there accordingly, 

 where the deposite has alone been worked, that we can collect 

 facts enough to lead to any general views of a practical bearing 

 regarding the structure of this coal field. Where our section crosses 

 it, — namely, through the estates of Mr. Wickham on Tuckahoe 

 creek, — the width of the coal tract is about four and a half miles. 

 It seems to expand in width as we follow it to the south side of 

 James river, being in a section drawn through the Black Heath 

 mines, probably eight miles across from the eastern to the western 

 outcrop of the primary strata, which compose the floor upon which 

 the coal-bearing group reposes. The probability is, that this is 

 nearly the centre of the basin, and the widest part of it, if we are to 

 judge from the fact, that the coal exists in greater thickness here 

 than at any place either further north or south. 



The thickness of these coal seams is very variable ; the great 

 lower mass which reposes within two feet of the primary rock, in 

 the Deep shaft and other adjacent mines in Chesterfield, is estimated 

 to be 40 feet from its upper to its lower surface. Over this there 

 is another thinner scam, five or six feet thick, separated by a few 

 feet of coal shale. A third, still thinner band of coal, is found be- 

 tween these in some of the mines. Upon the opposite or western 

 side of the basin, two separate seams are wrought in several of the 

 mines. At Anderson's mine, the upper seam varies from from six 

 to sixteen feet in thickness — the lower, separated from it by 30 feet 

 of slate and sandstone, is from four to eight feet, and rests almost 

 immediately upon the top of the primary rock. At Willis' and 

 Crouch's mines, on the south-east side of the coal field north of the 

 river, there are also two principal seams, the upper being five feet, 

 the lower about four feet thick, and separated from each other by 

 1 1 feet of slate. In both these points as elsewhere, the upper seam 



