130 Mr. Winch on the Geology of the Banks of the Tweed. 



formations, seem to vanish, and doubts are left upon the mind even 

 whether distinct epochs have at any period intervened between the 

 commencement and termination of the consolidation of secondary strata. 

 The mineralogical characters of rocks are now acknowledged to be no 

 satisfactory evidence of geological position, for by hand specimens, who 

 can point out the difference between the Red Sandstones, associated 

 with Coal and Encrinal Limestone at Berwick, or with Magnesian Lime- 

 stone in the county of Durham. If the mode of concretion is called 

 to our aid, we find the oolitic form is assumed, not only by the Lime- 

 stone usually denominated Oolite, but by the Magnesian Limestone at 

 Hartlepool, (Geological Transactions, vol. iv. p. '^,J and by the Encrinal 

 Limestone at Warcop in Westmoreland, as noticed by Mr. Fryer many 

 years since. Dolomite is interstratified with the Carboniferous or Encri- 

 nal Limestone in Derbyshire, as is Chert, in the Lead measures at Ark- 

 its thickness is about four feet, including a band of Stone of twelve inches in its middle. 

 This Seam of Coal is not reputed so good as No. 3. It has been worked, but to no con- 

 siderable extent, near Berwick. 



5th. The Cancer Coal is supposed to be from twelve to fifteen fathoms below the Stone 

 Coal, but the distance between them varies. The seam has not been worked in the east- 

 ern part of the district, lying at a considerable depth in that situation ; but at Thornton, 

 Shoreswood, Gatherick, and some adjoining places in the western part of the district, it is 

 worked under the name of the Main Coal. Its thickness is from five to five and a half 

 feet, and its quality is not good, the bed being traversed by thin bands of stone. 



6th. The Three-quarter Coal lies at variable distances below the Cancer Coal, being in 

 some places found at twelve, and at others twenty-two, fathoms deeper than that seam. 

 Its usual thickness is two feet eight inches, including a band of stone of ten inches ; its 

 quality is inferior to the better coals of the district. 



7th. The Cowper Eye Seam is generally met with about four fathoms below the Three- 

 quarter Coal ; it varies in thickness from two to three feet of saleable Coal, having a stone 

 band in its middle, unequal in thickness, but in some situations exceeding two feet. This 

 seam is chiefly worked in the western part of the district, as at Murton, Thornton, Shores- 

 wood, Felkington, Etal, Gatherick, Greenowalls, and their vicinity. In quality, it is con- 

 sidered equal to No. 3, Scremerstone Main Coal. 



No. 8. The Western Coal Seam appears to me to be the lowest worked in the district. 

 It has been sunk to at Shoreswood, and there found at about fourteen fathoms below the 

 Cowper Eye Seam, but the quality being indifferent, it was not thought worth working. 

 At Etal there is a mine carried on in it, though even there the coal is of inferior quality. 



From the gradual rise of the strata to the westward, the first four seams mentioned in the 

 section of the strata near Berwick, do not reach to Thornton, Shoreswood, Felkington, Etal, 

 Gatherick, and Greenowalls. Nos. 5, 6, 7, and 8, are the beds worked at those Coal Mines. 



