246 



THE GEOLOGIST. 



the coast from the little fringe of limestone and conglomerate-rock 

 at the Bathing House at l^ewton over the barren dunes of blown 

 sand through which the little river Ogwr enters the sea, we come again 

 on the same rocks; and as we leave the conglomerate, approaching 

 Dunraven Castle, we find the lias limestone resting partly on this 

 rock, and partly on the carboniferous limestone, without any inter- 

 mediate red sands or marls, so that, even if these latter deposits 

 existed, they must have been removed prior to the deposit of the 

 liassic strata. But to quote other instances of the degradation of the 

 chief rock-formations of the district is unnecessary, or to prove that 

 the destructive action produced by moving water had been actively 

 engaged in bringing about much of the present configuration of this 

 portion of the surface of South Wales ; it is right, nevertheless, to 

 point out the thick-bedded gravels which, though usually classed 

 under the general term of drift, probably represent the progress of 

 geological events far removed from one another in time. Of these, 

 however, one thing is certain, that in the districts in question the 

 massive beds of sand, small, flat, and sub-angular fi-agments of shale,* 

 which often carry proof of their original position in the roof of 

 some ancient coal-seam by being still flecked with coaly particles, — 

 pieces of clay-ironstone, pebbles, and patches of loamy clay which 

 spread wide over the low grounds, in places as much as ten yards 

 deep, are entirely composed of the debris of local rocks. Towards this 

 miscellaneous collection of rock fragments, the coal-measures and 

 the lias have contributed abundantly;* and although in the various 

 oscillations of land, which most likely occurred in bygone tertiary 

 times, the materials were more than once assorted duiing the varying 

 changes of level, yet, with the exception of the results of the action of 

 modem agents, we may look upon these gi'avels as evidence of the 

 last gi-eat modification of the surface. 



The cases are not many in which we have direct evidence afi'orded 

 us of a former phase in the physical geography of a country, by the 

 finding of the remams of animals still in the same positions as those 



hollows iu the Carboniferous hmestoue are similarly filled at Oakamore, near 

 Cheadle, and the argillo-sihceous sands are there largely quanied for use in the 

 potteries, from their possessmg highly refi-actory quahties for the manufactui'e of 

 hmnu-tik^s for the kilns. 

 * ivollcd sliclls of a species of Gryphrea are conimou iu the di'ift. 



