20 Mr. De la Beche on the Geology of Southern Pembrokeshire. 



found at Rosepool ; it intervenes between coal-shale and old red sandstone 

 at Langum ; is contorted together with limestone at Langum Ferry ; and is 

 seen on the edge of the coal-measures at Lawrenny Newton, These very 

 thick quartzose beds do not appear at Tenby ; siliceous grit of moderate thick- 

 ness, and shale containing two or three beds of limestone, forming there 

 tlie lowest of the coal-measures. The shale and limestone are seen between 

 the sluice-wall and the descent to the bathing machines. On the northern 

 edge of the coal-basin, from Mynwer to that part of Marcroes Mountain which 

 faces Pendine Cliffs, large blocks of compact quartzose sandstone are found 

 on the surface; and in Pendine Cliffs seven or eight beds of that rock are 

 seen supporting the other coal-measures. 



To the north of the western termination in St. Bride's Bay of the great 

 coal-basin, but separated from it by greywacke, a smaller coal district occurs, 

 which is probably connected with the great basin by intermediate submarine 

 strata, lapping round the greywacke of Druson. This district is bounded on 

 the west by the shores of St. Bride's Bay from Newgate Bridge to Druson 

 Haven. On the north-east it runs up from Brawdy Mill nearly to Eweston, 

 but it does not rise the hill at Broomhill, nor that above Brawdy Mill. The 

 tongue of land coming down from Eweston, and the valleys on either side, 

 belong to it. For the other limits of this district I refer to the Map. (PI. I.) 



Excepting a small space between Bathesland and Roche, where trap is 

 intruded, the whole of this smaller district is bounded by greywacke. The 

 coal-measures are often contorted, and at Druson Haven are set rather abruptly 

 on greywacke. (See PI. H. fig. 1.) Like the measures of the principal basin, 

 they yield only stone-coal. 



