﻿Vol. 6 1.] CONTIGUOUS DEPOSITS OF GLAMORGANSHIRE. 395 



Thickness in feet inches. 



( Marlstone, hard, greenish-grey, 



( Ostrea Bristovi (very 



ruon) ; Pteria (Avicula) 



massive at the top, but , 



? < nodular and mixed with black f 4 6 oporto (abundant in a 



g and yellow marl below J t Q hm ^r f *° *°P> ; 



| I Marls aid marlstones ^ %f^lL ' 



Large masses of marlstone from the Sully Beds, scattered about 

 on the beach, are crowded with Ostrea Bristovi, Etheridge, MS. (see 

 p. 422), and the beds also frequently contain traces of the mineral 

 baryto-celestine. These strata do not appear to have attracted any 

 attention ; they must have been observed, because Mr. E. T. Newton, 

 E.R.S., informed me that an Ostrea, similar to that which I had 

 submitted to him for examination from this locality, was preserved 

 in the Museum of Practical Geology, Jermyn Street, and bore the 

 legend ' Ostrea Bristovi, Etheridge, MS. Erom near Penarth/ In a 

 thin layer at the top of the Sully Beds, Pteria (Avicula) contorta is 

 very abundant. 2 Their fossil contents render it incumbent that 

 these beds should be classed with the Bhaetic, but an arbitrary line 

 of division must be drawn between them and the ' Tea-Green Marls,' 

 which will be subject to alteration according to the records of 

 fossils. 



(C) Cross Earm, near Dinas Powis. 



In the memoir descriptive of the geology of the Cardiff district 

 it is observed that 



' To the west of the Lower Penarth or Lavernock outlier there is a consider- 

 able tract just high enough to take in some of the Rhastic shales and limestones, 

 but nowhere high enough to touch the Lias.' 3 



Since the district was geologically surveyed between the years 1892 



1 Concerning this specimen, Dr. A. Smith Woodward, F.R.S., wrote (in 

 litt.) : — ' Premaxilla with cutting-teeth. Might be Sargodon, or perhaps a 

 Pycnodont fish.' It is preserved m the collection of Mr. E. Talbot Paris. 



2 The abundance of Pteria contorta in the uppermost layer of the Sully 

 Beds here, and the record by Mr. E. T. Howard, F.G.S., of ' numerous crushed 

 specimens of typical Rhcetic shells — Cardium rhceticum. Avicula contorta, and 

 Pecten valoniensis'' — in a thin layer of shale beloAV the 'fish-bed,' Trans. Cardiff 

 Nat. Soc. vol. xxix (1896-97) p. 66, is interesting in connection with a statement 

 made by Prof. S. H. Reynolds & Dr. A. Vaughan in a footnote to their admirable 

 paper on 'The Rbastic Beds of the South-Wales Direct Line' Quart. Journ. 

 Geol. Soc. vol. lx (1904) p. 200. In that footnote they remarked :— « We have 

 ventured to dissent somewhat from Mr. Richardson's correlation of the beds 

 at Garden Cliff. Seeing that Avicula contorta and Schizodm occur plentifully 

 below his Bone-Bed (Bed 15). it does not appear to us that this bed can be 

 considered to be on the same horizon as that at Sodbury, which is well below 

 the level at which these mollusca commence to occur in any abundance.' As to 

 whether the Sodbury Bone-Bed was on the same horizon as that numbered 

 15 at Garden Cliff was a question for them to decide, and the evidence which 

 led to their answer in the negative is quoted above. In view of the details 

 obtained in Glamorganshire (and also in the Watchet district), this hardly 

 seems conclusive. 



3 ' The Geology of the South- Wales Coalfield : Pt. iii ' Mem. Geol. Surv. 

 1902, p. 63. 



