﻿404 MR. L. RICHARDSON ON THE RH^ETIC AND [Aug. 1905, 



Between How Mill and The Herberts a road-section shows 

 sandy beds and shale : — 



Thickness in feet inches. 



a. Shale, black 



b. Sandstone, fine-grained, calcareous: -, ^ " \\ „ n^' 

 -. . . ' , to ' A -, and some other iish- 

 1 to 2 inches li • i , • -, , 



remains, but mdeter- 



c. Shale, grey 



K d. Limestone, arenaceous, nodular : 1 to 



I 111 in able. 



# 



2 inches 1 



e. Shale, black 1 



f. Sandstone, hard and dark-grey bands ( In the hard por- 



near the base, but otherwise some- j tions were noted 



what soft 6 Oncosts of a lamelli- 



! branch and numerous 

 ^ small pieces of wood. 



Keuper. I. Hard, grey, rocky marls 



As no distinctive fossils were obtained from these rocks, it is only 

 possible to say that they belong to the Lower Rhsetic. 1 



The sections in the railway-cuttings north and south of St.. 

 Mary-Church Road Station have been described in detail in the 

 Geological-Survey Memoir on the district 2 ; and, in both cases, 

 below the representative of the Paper-Shales of the Lavernock 

 Section, is the White Lias — shaly and marly matter constituting 

 the greater mass of the deposit. Owing to the ample details 

 recorded in the memoir just cited, it is unnecessary to discuss 

 these sections here ; and the same remark applies to the sections of 

 the Rhsetic Beds at both ends of the railway- cutting at Cowbridge. 3 

 That at the southern end is the more satisfactory of the two. The 

 Paper-Shales are 8 inches thick, and the Rhsetic and White-Lias 

 deposits between them and the Keuper measure 19 feet. 



Having dealt with the sections of the Rhaetic deposits in the 

 district between Barry and Cowbridge, I may now direct attention 



1 Higher up, in a field on the south side of the road, there is a quarry in 

 blue-limestones with shale-partings— the upper beds full of Psiloceras Johnstoni. 

 They are crowded with gasteropods, the commonest form of which is Cerithium 

 qratum, Terquem. In the quarry on the north side of the road, as noticed by 

 Mr. F. T. Howard, Trans. Cardiff Nat. Soc. vol. xxx (1897-98) p. 41, are 

 several limestone-beds crowded with Thecosmilia cf. irregularis, Duncan. 

 Halfway between Llandough-juxta-Oowbridge and Llanfihangel are two 

 quarries, one on each side of the valley. In that on the north side is a bed 

 full of the same species of Thecosmilia, while the other fossils included Pteria 

 (Avicula) incBquivalvis, Lima valoniensis, L. tuberculata, Modiola minima (?), 

 Pinna, Omithella sarthacensis, and radioles of an echinoid. The quarry on 

 the opposite side yielded Psiloceras planorbis, Lima gigantea (small), Pecten 

 aff. calvus i Pinna, Ostrea, Modiola minima, Sow., and a gasteropod. 



2 ' The Geology of the South-Wales Coalfield ; Pt. vi' (1904) pp. 41-44. 



3 Ibid. pp. 44-48 and Trans. Cardiff Nat. Soc. vol. xxx (1897-98) pp. 36 

 et seqq. 



