﻿38G MR. L. RICHARDSON OK THE RHSETIC AND [Aug. 1905, 



Gloucestershire and Worcestershire of certain beds at the base of 

 the Rhtetic Series. I then stated that 



' there is evidence to suggest that there were earth-pressures at work at the close 

 of the Keuper Epoch, which caused the deposits to be thrown into slight synclinal 

 and anticlinal flexures. In the depressed areas the earlier deposits of the Rhsetic 

 were laid down, and successive overlap on to the marls seems to have taken 

 place.' 1 



My reasons for suggesting this explanation for the phenomenon 

 were as follows. Throughout North- West Gloucestershire and 

 Worcestershire the component deposits of the Rhaetic are remarkably 

 persistent. There were slight earth-movements towards the close of 

 the Fteria (Avicula)-contorta age, it is true, which affected the persis- 

 tency of one or two beds ; but the cause for their irregularity is so 

 obvious, that it does not influence the matter under discussion. 

 Once below a certain stratum, however, such persistency is not to 

 be observed. That stratum happens to be full of saurian- and 

 fish-remains at certain localities, on which account it has been 

 denominated the ' Bone-Bed.' Therefore I employed this term, 

 or that of 'Bone-Bed equivalent,' according as the circumstances 

 demanded. The geographical distribution of these infra-Bone-Bed 

 deposits appears to me to be, at present, satisfactorily explained 

 only by the theory that I have formulated. 



For some years previous to the publication of the above-mentioned 

 paper, I had come to the conclusion that 



' when the Rhsetic ocean gained access to the British area it spread over an 

 undulating expanse of Keuper Marls. In some areas, however, . . . lakes 

 probably existed, and it would be in these areas that the complete sequence 

 from the Keuper to Rhaetic deposits should be looked for. The section of 

 deposits formed under the conditions stated would be essentially of transitional 

 nature, as at Watchet ; but where the Rhsetic ocean spread over the sur- 

 rounding ground a non- sequence would result. Thus, at the present time, the 

 junction-line would appear sharply defined ; there would be no transitional 

 signs, and practically no erosion.' 2 



A stretch of water, probably of considerable dimensions, extended 

 into the Lavernock district, and therefore, according to my 

 theory, transition-beds should be present. Such is the 

 case : the transition-beds are the ' Grey Marls ' (pars) of the late 

 Robert Etheridge. This term would have been a convenient 

 designation for the beds, had it not been generally misinterpreted. 

 But, as such is the case, it appears desirable to replace it by the 

 term ' Sully Beds/ after the locality where the most interesting 

 development can be studied. 



II. The Sully Beds. 



In his very interesting memoir of Robert Etheridge, Mr. H. B. 

 Woodward, E.B.S., drew attention to the fact that the ' Grey 

 Marls ' and ' Tea-Green Marls ' of Etheridge were distinct deposits. 



1 Quart. Journ. Geol. Soc. vol. lx (1904) o. 356, 



2 Ibid. p. 357. 



