TITTERSTONE CLEE COAL-FIELDS. 



113 



perfectly-formed, small basin. The whole of the space which is marked by a dark 

 colour upon the map is not, however, a productive coal-field, but includes those sand- 

 stones and millstone grits which support the coal, and which in this and all the other 

 districts cited in this work, are unproductive of coal 1 . The coal-field is flanked on 

 two sides by zones of carboniferous limestone rising from beneath the millstone grit, 

 and the base of the series is the Old Red Sandstone, which wraps entirely around the 

 tract, separating it on the north from the coal-field of the Brown Clee, on the west from 

 the Ludlow rocks, and on the east from the coal-fields of the Forest of Wyre. (See Map 

 and sections, PI. 30. figs. 1 and 6.) Thus the coal measures of the Titterstone Clee are 

 in portions of their range based upon those rocks which in other parts of England com- 

 plete the succession of the lower carboniferous strata. 



That portion of the field known by the name of Cornbrook, forms an elevated trough, 

 capped by a plateau of basalt. To the south-west of it, and at a considerably lower 

 level, is the small basin of elliptical form, called the Knowlbury field (PL 30. fig. 7.), 

 which is distinctly broken off from the great field of Cornbrook ; and hangs, as it were, 

 from the skirts of the more elevated tract. This basin is completely exempt from 

 basalt, except that its surface is partially encumbered with fragments of that rock. The 

 Gutter, Horse-ditch, and Blue-stone works are merely the thin or lower coal seams 

 which crop out at various points beneath the escarpment of the larger and overlying 

 basin of Cornbrook. In those parts of this coal-field which are most fully developed, 

 as at Cornbrook and Knowlbury, there are four principal beds of coal, which vary 

 somewhat in thickness in different parts of the district. In descending order they are 

 known by the names of the Great Coal, Three-quarter Coal, Smith Coal, and Four-feet 

 Coal. Although only four beds of good coal have been proved in any one shaft or 

 vertical section, there is reason to believe that the coal worked at the Gutter, Horse- 

 ditch, and Blue-stone pits is a fifth or still lower band, which thins out to the eastern 

 and southern parts of this field, and is merely worked at detached points upon the out- 

 crop or basset. The uppermost or Great Coal is usually overlaid by a considerable 

 mass of shale and thickly bedded whitish sandstone, known as the " great coal rock". 

 Beneath the great coal, the shale contains a good number of concretions of ironstone 

 of excellent quality, usually exhibiting " Septaria" within, and often containing impres- 

 sions of plants. They are called the " Three-quarter ironstone measures," because they 

 surmount the three-quarter coal. These ironstone nodules are repeated below this seam 

 of coal in the shale beds termed Clumpers. Then follows the Smith coal, so named 

 from its peculiar value in the manufacture of iron. The Smith coal is separated from 

 the " Four-feet" coal, by a thick mass of sandstone, with many impressions of plants ; 



1 The coal-fields in this region differ essentially in this respect from those of Yorkshire and the North of 

 England, where there are not only coal-fields in the millstone grit, and below it, but also in and throughout 

 the carboniferous limestone. 



