HARJDIVICKE'S SCIENCE-GOSSIP. 



199 



to have been hollowed out after the Keuper period, 

 and probably in much later times. Where it rests 

 on the Coal-measures it contains occasional pebbles 

 of sandstone. Here and there lime-kilns mark the 

 places where the pebbles of the conglomerate have 

 been burnt for lime. 



Near Llantrissant and Llanhary are iron mines. 

 Here horizontal beds of conglomerate and iron sand- 

 stone, resting upon the upturned edges of the Car- 

 boniferous Limestone, are worked for haematite. 

 This also occurs in pockets of the limestone. At 

 St. Hilary are old lead-workings, where the ore 

 was formerly obtained from the conglomerate. At 

 Hendre, north-east of Coyty, nearly forty feet of the 

 conglomerate may be seen. Close by, at Byeston, it 

 is interstratified with marl, and the same may be 

 seen in a railway-cutting near Llanharan. 



Red marls occur at Pyle, and in some places beds 

 of magnesian limestone and sandstone occur ; all 

 these varieties form an interchangeable group, which 

 evidently belongs to the Keuper division of the Trias. 



Rhcetic— The Rhretic or Penarth beds extend as 

 far westward as Pyle, where they have been des- 

 cribed by Mr. Bristow. Here they comprise lime- 

 stones, shales, and marls. At Gelligaredig they 

 consist of brown sands, resting on the green and 

 grey marls of the Keuper. In the outlier at Coed 

 Mwstr, white lias limestones are developed, asso- 

 ciated with greenish clay and conglomerate. At 

 Stormy Down the white lias has been noticed, and 

 beneath occur sandstones and marls with Anatina 

 pracursor, Avicula contorta, and fish-remains. The 

 white sandstones that are worked, near Bridgend, for 

 building and grinding-stones, are regarded by Mr. 

 Bristow as of Rhsetic age. 



LlASSIC. 



Loiver Lias. — The Lower Lias of Glamorganshire is 

 well shown in the cliff sections between Sutton and 

 Dunraven, with a thickness of about forty feet. At 

 Sutton the beds constitute a white and tufaceous free- 

 stone, which has been largely quarried, and was used 

 in the construction of Neath Abbey and Swansea 

 Castle. Eastwards the beds become darker and 

 contain fragments of chert derived from the Carbon- 

 iferous Limestone. In places the beds become very 

 conglomeratic, and De la Beche remarked on the 

 difficulty of separating the Dolomitic from the Lias 

 conglomerate. They contain Gryphcva incurva, 

 Ostrca liassica, Paten pollux, Lima gigantea, and 

 large ammonites. 



At Merthyr-mawr, Bonvilston, and other places, 

 the Lias assumes a crystalline texture, so like the 

 Carboniferous Limestone that it is difficult to separate 

 them. The beds at Sutton were at one time claimed 

 as Rhretic by Mr. E. B. Tawney,* but they have 



been shown by Mr. H. W. Bristow and Mr. C. Moore 

 to belong to the Lias, with which they were originally 

 classed by De la Beche.* 



Post-Pliocene. 



Glacial Drift.— But little attention has been paid 

 to the deposits of Drift scattered over the southern 

 parts of Wales, and I am not aware of any descrip- 

 tion of glacial beds in the immediate neighbourhood 

 of Swansea, beyond that of some patches of boulder- 

 clay found by Professor Prestwich on Cefn-y-bryn 

 and in Rhos Sili Bay, in Gower. t 



From Llandaff, by Cowbridge to Bridgend, and 

 north-west of Pyle, the rocks are much obscured by 

 boulder-clay, of irregular thickness. Often the soil 

 gives indication of drift, when a quarry close by 

 shows no trace of it. Thus in the railway-cuttings 

 between Ystrad Owen and Cowbridge, Drift alone 

 is seen in some places, and in others the Lias comes 

 up to the surface. This Drift is a clay with boulders 

 of grey sandstone, quartzose conglomerate, cherty 

 sandstone, and quartzite ; derived from the Old Red 

 Sandstone, Millstone Grit, and perhaps Coal-measures. 

 All these are local rocks ; the Carboniferous Lime- 

 stone is very rarely represented in the Drift. 



Towards Welch St. Donats and Pendoylan the 

 ground, hill and valley, is covered with Drift ; 

 sometimes this is sandy and contains subangular 

 blocks of red sandstone and cherty rock, and some- 

 times the ground is very boggy. The Drift here 

 corresponds in character with that seen in the neigh- 

 bourhood of Tiverton in Devonshire. Mr. Bristow 

 informed me that he and Professor Ramsay found 

 Coal-measure sandstones with glacial strice in the 

 boulder-clay near Cardiff.t 



Caverns. — The Carboniferous Limestone of Gower 

 is well known to contain a number of caves, fissures, 

 and holes — some inland, most of them on the coast — 

 nearly all of which have yielded bones of animals 

 long since extinct in this country. The Goat's Hole 

 at Paviland was explored by Buckland in 1823, and 

 he then obtained specimens of the woolly rhinoceros, 

 hycena, cave-bear, and mammoth. Many years 

 later several caves were systematically explored by 

 Lieut. -Col. Wood and Dr. Falconer. In addition to 

 the forms before mentioned, they obtained Rhinoceros 

 heviihcchus, Elephas antiquus, Hippopotamus, and, 

 in one fissure, called Bosco's Den, about one thousand 

 antlers of a variety of the reindeer.§ At Long Hole 

 flint implements were found in association with the 

 two species of rhinoceros just mentioned. In the Isle 

 of Caldy is a cavern with numerous fine stalactites 

 and stalagmites. 



* Quart. Journ. Geol. Soc. vol. xxii. p. 69. 



* Bristow, Ibid. vol. xx : .ii. p. 169; Moor;, Ibid, p. 511. 



t Quart. Journ. Geol. Soc. vol. xvi. 



J Geol. Mag. vol. ix. p. 574- 



1 Quart. Journ. Geol. Soc. vol. xvi. p. 451. 



