58 Rev. A. Sedgwick on the Geological Relations and 



though probably belonging to a lower part of the formation, was formerly worked near Water 

 Fryston by means of a pit sixty yards deep. Though this pit commenced so far within the 

 general limits of the limestone, the form of the country, and a knowledge of the inferior strata, 

 may naturally have led to an expectation of meeting coal-beds at no great distance below the 

 surface. 



6. Between Pontefract and the valley of the Wharfe, the magnesian limestone ranges in a direc- 

 tion about N. and by W., over one of the richest divisions of the Yorkshire coal strata. In the 

 same part of the field the average bearing of these strata is nearly N.E. ; and their dip, with 

 many flexures and irregularities, is nearly S.E.* In consequence of this relative position, the 

 successive deposits of the coal formation necessarily range up to the base of the magnesian terrace : 

 and that they pass under it without any change in their physical characters is proved, not merely 

 by the analogy of the neighbouring country, but by many ancient and modern works, which, at 

 Glass Houghton, Kippax, Church Garforth, and Parlington, have been sunk through the lime- 

 stone into the lower formation. 



A detailed account of the several sections exhibited at these places might form the subject of a 

 distinct communication, but would be incompatible with the object of this paper. The following 

 short notice of them will be sufficient for my present purpose. 



There were formerly some collieries in Pontefract park ; and many shafts were afterwards sunk 

 in the low ground near Glass Houghton. As these works were exhausted, it became necessary 

 to sink further upon the dip ; and several pits were sunk on the skirt of the magnesian limestone : 

 the newest work of this kind (at a place called High-Field) is considerably to the east of the 

 escarpment. By these excavations, and still more by borings carried down to the lower beds of 

 the neighbouring coal-field, it is ascertained that the whole carboniferous strata pass regularly 

 under the limestone, with a mean dip towards the south-east of nearly one yard in twenty f. 



Several extensive coal-works have been carried on in a lower part of the formation near 

 Kippax. In consequence of a great flexure (which does not appear to affect the superincumbent 

 limestone) the beds are tilted at a considerable angle towards the north ; and the same seam of 

 coal is found in the lower ground on the south side of the village, about twenty yards from the 

 surface, which was formerly worked by pits sunk through the yellow limestone and other lower 

 strata to the depth of nearly a hundred yards J. 



Between Kippax and Aberford many ancient coal-pits (all of which are, I believe, now 



* See the accompanying map. (Plate IV. No. 2.) The general bearing of the subordinate parts 

 of the Yorkshire coal strata may be seen in Smith's valuable geological map of the county, 

 t The following is a rough sketch of the strata passed through by the High-Field pit. 



1 . Yellow limestone 16 yards. 



2. Yellow sand , 4 



3. Blue bind, with some purple-coloured sandy micaceous beds .... 7 or 8 



4. Light yellow and grey sandstone, containing a few concretions"] 



of sparry iron ore, and near the bottom passing into a harder ^ 30 



brown sandstone J 



5. A very impure coal (not worked) 5 feet. 



6. Blue bind 2 yards. 



7. Good coal 18 inches. 



Forty-eight yards below the 18-inch coal (No. 7.), there is an impure 3-foot coal; and 



sixty-five yards still lower, there is a 5-foot coal. These two last beds have been proved by 

 boring. 



I One of the old pits on Kippax Hill was said to pass through thirty yards of limestone, and 

 six feet of light yellow sand ; below which were the regular coal-measures, consisting of blue 

 bind, shale, and slaty sandstone. In general, the thickness of the limestone was not so great. 



