Mr. N. Wood on the Geology of Northumberland, S^c. 323 



I shall now endeavour to corroborate the preceding assumption of 

 the extent of the lower beds of the Coal Measures to the west, and the 

 position of the Red Sandstone of the Tweed, by tracing some of the 

 most prominent strata through the district intervening between the two 

 lines of Section. 



It will be observed, that in the Alston Moor district, immediately 

 below the " Little Limestone," and between it and the " Great Lime- 

 stone," there occur traces and indications of Coal, called the High and 

 Low Coal Sills. The position of these Coal Sills is, therefore, below the 

 second bed of Limestone in the series. Under the first bed of Lime- 

 stone there is also found a thin bed of Coal. These Coal Sills, which 

 in Alston Moor exhibit only traces of Coal, on the north side of the 

 line of Dykes produce workable beds of Coal, especially those which 

 lie below the second bed of Limestone. The working of the different 

 Coal Pits, which have been sunk to this Coal, will enable us to trace these 

 Coal Sills and their accompanying beds of Limestone through the 

 district, which I shall endeavour to do from west to east. 



In Forster's Section of the Alston Moor district, the Great Lime- 

 stone lies about 22 fathoms below the Little Limestone and Coal Sills ; 

 this distance, however, varies much, as will be seen by a reference to Sec- 

 tions in different parts of the same district. A bed of Limestone, agreeing 

 in character with the Great Limestone, is quarried at Clowsgill, near 

 Talkin ; 26 fathoms above this lies the bed of Limestone enumerated 

 in the Talkin Section, having a Coal seam 40 feet below it. This Coal 

 bed, which is that worked, as before noticed, at Tindal Fell, Talkin, 

 and Geltsdale, I consider belonging to these Coal Sills, having a bed of 

 Limestone agreeing with the Little Limestone above it, and a thick bed 

 of Limestone below, agreeing with the Great Limestone. The position 

 of this Coal and Limestone, rising from underneath the Grit Rocks and 

 Coal Measures of Midgeholme, corroborates this assumption. 



Proceeding eastward from Talkin, we find a seam of Coal worked at 

 Blenkinsopp, having similar beds of Limestones above and below, 

 which, from the direction of the strata, leaves little doubt of being 

 identical with that of Talkin. The thickness of the seam is here 3i 



VOL. I. XX 



