Reports c& Proceedings — Geologists Association. 189 



* Geologists' Association. 



January 2, 1920. 

 " The Liassic Rocks of the CardifE District." By A. E. Trueman, 

 D.Sc, F.G.S. 



The greater part of South Glamorganshire, from Cardiff westwards 

 to beyond Bridgend, consists of Lower Liassic rocks (Hettangian 

 and Lower Sinemurian), which are well seen in some 20 miles of 

 magnificent cliff sections. Only meagre descriptions of these rocks 

 have been hitherto published. A detailed study has been undertaken, 

 first because nowhere else in this country are such continuous sections 

 of these rocks available, and secondly because the normal deposits 

 consisting of limestones and shales seen near Cardiff, when traced 

 westwards, pass into littoral facies or massive limestones and 

 conglomerates. In the present communication an account of the 

 normal Liassic rocks of the Cardiff district is given, as this will form 

 a basis for the correlation of the modified deposits further west. 



The Liassic rocks near Cardiff occur in several outliers, the chief 

 being those at Penarth, Lavernock, Leckwith, and St. Fagans ; 

 the sequence in the two former is clearly seen in cliff sections, and 

 in those localities there exists an almost complete transition from 

 Keuper to Lower Lias, so that they have become classical localities 

 for the study of the Ehsetic beds. In the cliffs at Lavernock, where 

 the Liassic sequence has been most fully examined, the rocks are 

 seen to form a gentle syncline, and since many of the limestone 

 bands form extensive reefs on the beach it is an easy matter to collect 

 fossils in place. 



The general sequence at Lavernock and in the neighbouring 

 outhers is as follows : — ■ 



Feet. 

 Nodular limestones and shales, mainly ayigulatus zone, about 40 

 Lavernock Shales, angulatus zone, with Waelmeroceras 



in the lower portion . . . . . . ,, 40 



Nodular limestones and shales with Caloceras cf. 



Johjistoni . . . . . . . . ,, 18 



Limestones and shales with PsiZoceras cf. j^Zanorfce . ,, 5 

 Limestones and shales (Osirea beds) . , . . ,, 21 

 White Lias ,,9 



Liverpool Geological Society. 

 February 10, 1920.— Mr. W. T. Walker, B.Sc, F.G.S., President, 



in the chair. 



The following paper was read : '' Dumb-bell Islands and Peninsulas 

 on the Coast of South China." By Walter Schofield, M.A. 



The paper records observations made during a residence of several 

 years in Hong-Kong, in the neighbourhood of which the " dumb- 

 bell " island and peninsula — a physical feature of the coast of 

 South China which attracts attention by its frequency — are 

 especially common. 



A " dumb-bell " may be defined as two land areas connected 



