250 Messrs. Buckland's and Conybeare's Observations on the 



The A^orf/ierw Coal-tract, which is the most extensive and elevated, compre- 

 hends the collieries of Iron Acton^ Sodbury, and Kingswood. It extends in 

 length nearly \2 miles, from the northern apex of the basin at Cromehall near 

 Tortworth to the village of Brislington, on the left bank of the Avon, near 

 Bristol. Its breadth from east to west, in the parallel of Sodbury, where it is 

 the greatest, is nearly 4 miles. The coal-measures are exposed in immediate 

 contact with the limestone along the northern limits of the basin from Sodbury 

 to Cromehall and Titherington ; but on the western, southern, and great part 

 of the eastern border of the tract, they are skirted by hills of red marl capped 

 by lias, through both of which formations, at Pucklechurch on the eastern 

 border, shafts are sunk to the coal. To the south of this coal tract, at Brisling- 

 ton, the red marl and lias form a table-land, supporting the loftier oolitic sum- 

 mit of Dundry-hill. 



The Central Coal-tract commences on the south of Dundry-hill and of the 

 table-land of lias, at the foot of their descent towards the vale of the Chew 

 river. It consists of two portions connected by a narrow valley : the northern 

 extends in length about 6 miles, from Burnet on the north-east towards Knowl- 

 hill near Stanton Drew on the south-west, and is about 2 miles broad near 

 Pensford. The southern portion extends about 3 miles, from Temple Cloud on 

 the west to between High Littleton and Timsbury on the east. Both these 

 portions and the valley connecting them, are bounded by ranges, which towards 

 their bases consist of red marl, but are capped towards their summits by lias, 

 bearing occasionally still higher platforms of inferior oolite. 



To the south-east of this central coal-tract, through an interval of 6 miles, 

 the coal-measures are entirely concealed by the overlying deposits. Throughout 

 the whole of this interval, however, every valley abounds with shafts, which 

 are sunk through the red marl into the coal-measures ; and many are begun 

 on the summits of the platforms of lias. Of the latter kind several occur in the 

 parishes of Timsbury and Paulton ; but the deepest is on Clan Down near 

 Radstock, which begins in the upper part of the lias, close to its junction with 

 the inferior oolite, and is sunk 200 fathoms before its horizontal adits begin to 

 be thrown out. On the edge of the same down, towards Paulton, is a shaft 

 which begins in the oolite, but is much less deep than the former ; the coal- 

 seams, owing to a rise of the strata in this direction, here approaching much 

 nearer to the surface. As we approach the Mendip Hills, the coal-measures 

 are denuded to the extent of about an acre on the ascent of the hill above 

 Chilcompton, on the road to Midsummer Norton ; and at length are again ex- 

 posed in the southern coal-tract, which extends from west to east nearly 6 

 miles, beginning a little below the point where the Nettlebridge stream is 

 crossed by the road from Bath to Shepton-Maliet, and ending between Vobster 



