216 Reports and Proceedings. 



the gravel, which contains pebbles of all sizes, was derived from the 

 disintegration of the rocks of the district ; and (3) that, judging 

 from the richness in gold of paying drift in California, it is probable 

 that these auriferous gravels will pay also. 



2. " On the discovery of Coal on the Eastern Slope of the Andes." 

 By W. Wheelwright, Esq. Communicated by Sir R. I. Murchison, 

 Bart., K.C.B., F.R.S., etc. 



In this paper the author reported the occurrence of beds of Coal 

 on the eastern slope of the Andes, between the cities of Cordova 

 and San Juan, about twenty-five leagues east of the latter city. 



3. " On the presence of Purbeck Beds at Brill. Buckinghamshire.' 

 By the Eev. P. B. Brodie, M.A., F.G.S. 



The existence of the Purbeck-beds at Brill not having been yet 

 accurately determined, the author recorded their occurrence in that 

 locality, which he had been able to ascertain by finding blocks 

 containing several species of Purbeck freshwater shells, especially 

 Paludina suhangulata and Cyrena media. 



4. " On the Lower Lias, or Lias-conglomerate of Grlamorgan- 

 shire." By H. W. Bristow, Esq., F.E.S., F.G.S., of the Geological 

 Survey of Great Britain. 



The object of this communication was to show that the more or 

 less conglomeratic strata immediately underlying the ordinary Lias 

 limestone on the coast of Glamorganshire, between the River 

 Ogmore and Dunraven Point, do not belong to the Rhaetic series, as 

 has been supposed, but to the Lias. 



The Sutton-stone of Sutton and the so-called Southerndown series 

 (seen in the cliffs under the hamlet of that name) constitute, in 

 reality, but one series, the stratigraphical position of which is proved 

 by reference to the sections at Cwrt, near Langan, at St. Mary Hill 

 Common, west of Trymynydd, and at the Stormy Cement Works, 

 where it immediately overlies the Rhastic series, while its palseonto- 

 logical affinity with the Lias is proved by the occurrence throughout 

 its entire thickness of the most characteristic shells of that formation, 

 viz., Gryphcea incurva, Ostrea Zdassica, Lima gigantea and Ammonites. 



These conglomeratic strata extend over a large area from Sutton 

 to beyond Cowbridge ; and wherever the Lias rests upon Carboni- 

 ferous Limestone or Magnesian Conglomerate, it assumes an ab- 

 normal lithological character, and becomes more or less conglomeratic. 

 The replacement, in this district, of the ordinary calcareous and 

 argillaceous sediments, of which the Rheetic and Liassic series are 

 usually composed, in the former case by sandstones, and in the 

 latter by conglomerates, indicates that they are the near-shore and 

 shallow-water deposits of an area that now forms part of South 

 Wales, and which was partially undergoing slow depression during 

 the deposition of the Lias. 



After noticing the occurrence of lead-ore (Galena) in these beds, 

 the term Lias Conglomerate, originally applied to them by Sir 

 Henry De la Beche, was proposed as being sufficiently precise and 

 distinctive, the name Infra-lias, by which they are sometimes denoted, 

 being objected to, as being both vague and misleading. 



