244 A Geological Description 



the name of a sandstone than pudding-stone. From the river 

 side tlie pudding-stone can be traced crossing the road a httlu 

 below Leigli. It is tlicn (or some distance lost on accoxint of 

 the cultivated state of the country, but in the hills near Pill and 

 St. George's it is very distinctly seen, and can be followed be- 

 yond Porthurv. In this route the pud(Jiiig-stone is always seen 

 dipping under the limestone agreeably to its inclination. 



We now return to the stratitication at the river's side. Be- 

 yond the pudding-s'tone which continues for about 200 yards, 

 \\c arrive at the red sandstone of a fine friable texture, and 

 containing spangles of mica. We can follow this rock north- 

 westward from the river, and always see it sinking under the 

 pudding-stone. It is exposed in n)any places in the space be- 

 tween Leigh and Portbury, and I have remarked this rock un- 

 derneath the limestone at Mendip Hills in the path leading 

 from Langford to Shipham. 



I have been thus particular in describing these formations, as 

 they absolutely exhibit a counter part of those that exist in the 

 south of Herefordshire, along the skirts of Dean Forest. I had 

 lately an opportunity of investigating the geology of the hilly 

 country in the neighbourhood of Ross, and could not but be very 

 much struck with the almost perfect identity of the series I have 

 just now described with that near Ross. The lowest strata of 

 which those hills were composed was the red sandstone I have 

 just been dwelling u))on. Then succeeded a sihceous pudding 

 consisting of rounded pebbles of quartz, united by a sandstone ce- 

 ment, and above the pudding-stone lay the mountain limestone. 



It is probable that the same stratification obtains in the coun- 

 try about Chepstow, for the mountain limestone is seen to pre- 

 vail there, and I observed that Tintern Abbey is built of the red 

 sandstone, which I was informed was quarried from the neigh- 

 bourhood. 



Having now fully described t.he limestone and the relation 

 which the other inclined strata bear to it, I have next to speak 

 of the country which the limestone ellipsis incloses. It is al- 

 most entirely an extensive coal formation, in which the coal either 

 occurs in regular basins, or in veins following each other in quick 

 succession, without being arranged in any determinate form. 

 Mr. Townsend has described a very beautiful instance of the 

 first kind of formation on the north-east side of Bristol, the 

 outer range of which will be described by a line beginning at 

 Iron Acton, and drawn through Vatc, Wapley, Pucklechurch, 

 Mangotsfield, Hambrock, and Frampton. This basin is about 

 five miles in length and four in breadth, and in every part of its 

 circumference 1 found the coal and its accompanying strata 

 tending to a common centre. The Nailsea coal-field which ia 



inclosed 



