Vol. 60.] THE KEUPER AND RHJ.TIC IX GLOUCESTERSHIRE, ETC. 357 



consequently, sections by quarrying and mining are few in number ; 

 river-cliffs, railway- and lane-cuttings afford the best exposures. 

 If there were anything like half the number of sections that are 

 obtainable in the Inferior Oolite of the Cheltenham district, this 

 theory. I venture to think, would have had more facts to support 

 it. At one time I was inclined to believe that — allowing, of 

 course, for unequal deposition — the several beds of the Rhaetic 

 Series seen below the Bone-Bed had been deposited over the greater 

 part of England ; but that subsequent to their deposition they had 

 been thrown into slight synclines and anticlines, and that after 

 the anticlines had suffered erosion the Bone-Bed was deposited non- 

 sequentially.over the whole. This view I now consider improbable. 



In my opinion, the evidence obtainable suggests that it was the 

 Keuper deposits which were thus affected ; and in immediate pre- 

 Rhaetic times. According to. my theory, when the Rhaetic ocean 

 gained access to' thV British area it- spread over an undulating ex- 

 panse of Keuper Marls. In some areas, however, it has been stated, 

 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 Rhaetic ocean spread over the surrounding 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. As the area sank gradually the Rhaetic ocean 

 slowly encroached upon the land-surface, and successive overlaps and 

 oversteps resulted. The lower deposits of the Rhaetic Series now ex- 

 posed at Garden Cliff and Chaxhill appear to have been laid down in 

 a relatively much-depressed area between the Palaeozoic barrier and 

 the anticline, somewhere in the Denny-Hill and Lassington district. 

 If sufficient sections had been obtainable between Chaxhill and 

 Denny Hill, this successive overlap should have been observable. 



It seems probable that it was during the formation of the Bone- 

 Bed that the greatest overlap took place. In the sections at Xew 

 Clifton (Bristol), and again in the railway-cutting at Lilliput, the 

 Bone-Bed is seen to encroach considerably upon what was, at one 

 time in the Rhaetic Epoch, land composed of Palaeozoic rocks. The 

 1 Tea-Green Marls ' of Sedbury Cliff do not appear to have been 

 submerged until the time when the Bone-Bed was formed ; and 

 such would appear to be the case with many sections in the Bristol 

 district also. The Keuper Marls of Gold Cliff, near Newport, may 

 have been submerged about this time, for into their fissured surface 

 J. E. Lee noted that Bone-Bed material had been washed. 1 A 

 certain amount of littoral action is shown by the formation of a 

 conglomerate such as that at Aust and Sedbury Cliffs. At Denny 

 Hill the Bone-Bed contains small pieces of derived marl. 



There is one other point to which I would direct attention. At 



1 Rep. Brit. Assoc. (Brighton, 1872) Trans. Sections, p. 116 ; and ' Xote-book 

 of an Amateur Geologist " 1881. p. 72 & pis. clxxi-clxxii. 



