Mr. W. Peile on a Transformation of Coal. 179
and without the preface of any small hitch, as shewn in the Diagram, No. 1, Plate III.
The change is most singular in the Master Band, because the metals, or bands, intersecting the seam, are in no way altered; the Coal only is turned into Stone.
In the specimens,* No. 1 is of the top Stone, No. 2 of the middle, and No. 3 of the bottom Stone.
The Crow Band being a pure seam, without metals, exhibits after the change, a solid stratum of Stone.
I could not trace any connexion between the two seams at the point of changing; the strata between them seemed unaltered and regular.
As the Main Band has never been wrought under this part, it is not proved whether the same occurs in it also, but it was not found in the old Main Band Colliery to the rise, where, according to its line of direction, it might have been expected. I had an account of the Coal being somewhat inferior in quality there, but the only irregularities were a small hitch, and a white freestone "Rib," or Dyke, about 12 inches thick, standing perpendicularly through the seam, but they are probably not connnected with it, as they occur in other parts of the Colliery.
The breadth of the Stone Bands continues the same, till the outcrop of the two Seams.
These irregularities seem to be coeval with the deposition of the
Seam, and thus distinct from Dykes which have evidently been formed long afterwards; but that there is some connexion between the Freestone "Ribs" or Stone Dykes, and the Slips, must be inferred by the former being found invariably where the strata are much confused by the action of the latter. I have added a section of a Stone Dyke found in the William Pit, at Whitehaven (see Diagram No. 2, Plate III.) as cut through in working the Coal, and which may also be seen at the surface, having passed through all the intermediate strata in a perpendicular direction. Like the riders described in a former paper,† it is in
* These numbers refer to specimens which accompanied this paper, and are deposited in the Museum of the Society,
† Vol. i., page 160.
