Reports and Proceedings — Geological Society of London. 333 



differentiated magma. There are clear evidences of some further 

 differentiation in situ, but the full extent to which this took place 

 offers a large field for future investigation. 



2. " The EliEetic and Contiguous Deposits of Glamorganshire." 

 By Linsdall Richardson, F.G.S. 



The principal sections in the county are described in detail, the 

 chief being those at Lavernock (near Cardiff), Barry, Tregyff (near 

 Cowbridge), Quarella (Bridgend), and Stormy Down. The Sully 

 Beds, a name given to the fossiliferous portion of the ' Grey Marls ' 

 of Etheridge, are determined to belong to the Rhajtic Series, on 

 account of the fossils that they contain. They are quite distinct from 

 the 'Tea- Green Marls,' in which fossils have not been observed. 

 Earth-pressures affected the rocks during the formation of the Sully 

 Beds ; the Avicula contorta black shales rest upon them with perfect 

 parallelism, but even then non-sequentially. Owing to an up- 

 heaval of the Lavernock district early in the age in which the 

 Upper Rhgetic Stage was deposited, only a portion of the lowest 

 bed of that stage is found, and this deposit was subjected to sub- 

 aerial denudation during the accumulation of the remaining Upper 

 Rhgetic beds elsewhere. But subsidence again in the same district 

 allowed of the deposition of the White Lias, and as a result this 

 latter rests non-sequentially upon a portion of the lowest part of 

 the Upper Rhsetic deposit. The White Lias, at certain localities 

 in Glamorganshire, contains in abundance PUcatula iniusstriata, 

 PI. hettangiensis, and Lima valoniensis. The deposit intervening 

 between the Sun Bed and the Upper Rheetic near Bath (Newbridge 

 Hill) is over 11 feet thick ; at Lavernock the equivalent deposit 

 measures but 2 feet 2|- inches. At Lavernock, however, above the 

 probable equivalent of the Sun Bed, are marls 6 feet 4 inches thick, 

 which are provisionally grouped with the White Lias. Above come 

 the Paper Shales, succeeded by the Ostrea Beds. The Upper Rheetic 

 of North- West Gloucestershire and Worcestershire is not the equiva- 

 lent of the White Lias of this or of the Bath district. The White 

 Lias occurs above the Cotham Marble (the topmost bed of the Upper 

 Rhgetic) and below the Paper Shales (which occur immediately 

 below the Ostrea Beds). Palseontological notes on certain of the 

 fossils are appended, including Ostrea Bristovi, Etheridge MS., 

 which is very abundant in the Sully Beds. 



3. "On the Occurrence of Rhaitic Rocks at Berrow Hill, near 

 Tewkesbury (Gloucesteishire)." By Linsdall Richardson, F.G.S. 



About 2 miles south-east from Chase End Hill (Malvern Hills) 

 there is a small outlier of Lower Liassic and Rhaetic beds, in 

 a basin-shaped area, supported and surrounded by Keuper Sand- 

 stone. A detailed section is given, mainly obtained by excavation, 

 and this is compared with the nearest locality where the whole 

 of the Rhgetic may be studied, namely, at Waiulode Cliff. At 

 Berrow Hill rock at the base of the Lower Rhsetic, at least 3^ feet 

 thick, is missing ; consequently Bed 13 rests directly, and with 

 perfect parallelism (so far as can be seen), but non-sequentially, 

 upon the 'Tea-Green Marls.' 



