200 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 20, 



doing so to acquire a knowledge which might, possibly, assist me in 

 surveying their westernmost extension, where I had already made a 

 cursory examination of them two years previously, in company with 

 the Director General of the Geological Survey. 



In tracing the coast-section from west to east, i. e. from the 

 Eiver Ogmore to Dunraven Point, instead of the strata being divisi- 

 ble into two separate and distinct series, as described by Mr. Tawney 

 in his memoir, and represented in the engraved sections which ac- 

 company it, there is, in my opinion, but one series ; that is to say, 

 there is not a Sutton Series (seen at the cliff at Sutton), and another 

 or Southerndown Series (seen in the cliffs under the hamlet of that 

 name) intervening between the Sutton Stone and the acknowledged 

 Lias ; but the beds occupying the cliffs at Sutton pass, in their hori- 

 zontal extension, into those forming the cliffs of Southerndown ; so 

 that there is, in fact, but one series, by whatever name it may be 

 called, the so-called Southerndown Series being merely the easterly 

 prolongation and the representative of the Sutton Stone of Sutton. 



That this is the case becomes equally apparent on examining the 

 coast- section from east to west, from Dunraven Point to Sutton. 

 The error fallen into by Mr. Tawney has been caused, perhaps, by 

 the exceptional and peculiar character of the stone exposed in the 

 quarries at Sutton, where it is soft, white, and tufaceous, and assumes 

 the texture of a freestone. Such a stone it is, in fact ; and a favour- 

 able specimen of its excellent quality and appearance is displayed 

 in the pulpit of the church at St. Brides Major, which is carved out 

 of Sutton Stone. 



Within a very short distance of the houses east of Sutton, the 

 stone becomes blue and hard, and assumes a closer texture; but 

 beyond that point and up to the caves which have been worn out 

 of the Carboniferous Limestone, upon the upturned edges of which 

 it has been deposited, the Sutton Stone is again white and tufaceous : 

 in an easterly direction from the caves it assumes a close texture, a 

 blue or blue-grey colour, and becomes extremely hard and tough. 

 Perhaps this change of character may, in some degree, be owing to 

 the influence of the sea- water, which washes the base of the cliffs 

 between the caves and Dunraven Point ; while westward of the 

 former the Carboniferous Limestone and Dolomitic Conglomerate 

 form the cliffs, and the Sutton Stone at the quarries recedes from the 

 shore, and is removed from the influence of the sea-water*. The 

 effect produced upon the strata by the sea-water has been to silicify 

 them, and to render them so hard that it is exceedingly difiicult, 

 and often next to impossible, to hammer the fossils out of the rock ; 

 while the calcareous shells of the fossils themselves, between high- 

 and low-water-mark, have sometimes been replaced by chalcedony 

 somewhat resembling that form of it which has received the name 

 of Beekite. 



But, irrespective of this supposed action of the sea-water, the strata 

 themselves are naturally much impregnated with siliceous matter, 



* It there forms the southern slope of the hills and rising ground which ex- 

 tend from the shore in a northerly direction. 



