Reports and Proceedings — Geological Society of London. 285 



Gold-bearing alluvia are briefly described, and the gold is sup- 

 posed to have come from the hills. The Adjah Bippo, Takwa, and 

 Teberibie formations are considered to be part of a syncline. Some 

 conclusions are drawn as to the method of formation and probable 

 auriferous chafacter of the rocks. 



II.— May 4, 1898.— W. Whitaker, B.A., F.R.S., President, in the 

 Chair. The following communications were read : — 



1. "The Carboniferous Limestone of the Country around Llan- 

 dudno." By G. H. Morton, Esq., F.G.S. 



Llandudno is so well known and frequently visited, that the 

 Carboniferous Limestone and the subdivisions into which it is 

 divided by clear lithological characters may be more easily examined 

 there than at any other similar locality. The subdivisions of " Lower 

 Brown," " Middle White," and " Upper Grey," along the broad belt 

 of limestone from Llanyraynech to Prestatyn, and around the Vale 

 of Clwyd, Abergele, and Llandulas, have been so frequently described 

 in the Proceedings of the Liverpool Geological Society that it is 

 unnecessary to give any general description of them. At Llandudno 

 the precipitous Great Orme's Head presents fine sections of the 

 Carboniferous Limestone and the subdivisions referred to, and may 

 be easily examined (with the aid of the appended geological map), 

 in a continuous series of cliffs, ridges, and quarries. The entire 

 succession is, however, not perfect, for the highest beds of the 

 " Upper Grey Limestone " have been denuded, and at the Little 

 Orme's Head. the subdivision is altogether absent. 



Copper-lodes on the Great Orme's Head appear to have been 

 w^orked by the Romans, and again in recent years until abandoned 

 fully thirty years ago. Some of the lodes are faults, but little can 

 be ascertained about them now, and only two or three are faults with 

 any appreciable amount of dislocation. It is to the undulation of the 

 limestone that the ever-varying dip of the beds is attributed. 



Numerous fossils occur in the "Upper Grey Limestone," and a few 

 are peculiar to the subdivision and the locality, but of these- only 

 a single specimen of each has been found. Productus margaritaceus 

 is abundant, though only an occasional species in other localities, 

 and not found at a lower horizon anywhere else in North Wales. 

 Other species, such as OrtTiis Michelini, formerly supposed to be 

 peculiar to the " Upper Grey Limestone," have been found at the 

 base of the " Middle White Limestone," at the Flagstaff Quarry on 

 the Marine Drive, near the Happy Valley. 



The dolomitization of the Carboniferous Limestone is remarkable, 

 and almost peculiar to that around Llandudno, though it also occurs 

 at Penmon in Anglesey. The " Lower Brown Limestone " has been 

 almost entirely converted into dolomite, and portions of the over- 

 lying subdivisions. The filling of the faults has often been changed 

 into dolomite, and the alteration of the Limestone has generally been 

 very capricious : the author's opinion being that the change took 

 place after the dislocation of the strata in post-Triassic times. 



