218 MR. A. STRAHAN ON THE ORIGIN OF [May rgo2, 
conclusions I agree closely with the views expressed by Sir Andrew 
Ramsay in 1872." 
In speaking of the later Secondary rocks, he stated his opinion 
that it was ‘even possible during the Upper Cretaceous period 
Wales may have sunk almost entirely beneath the sea.’ This 
hypothesis, so guardedly put forward, is likely I think to receive 
support. The Upper Cretaceous rocks, though they thin westward, 
are well developed at Haldon in Devon. ‘They have there over- 
lapped all the older Secondary formations, except a small part 
of the Red Rocks, and must obviously have overspread much of the 
Paleozoic area. In the Midlands also, as well as in the North- 
eastern Counties referred to by Ramsay, they overlap the Upper 
Jurassic strata with a marked unconformity, while finally they 
re-appear in Scotland and the North of Ireland. This overlap by, 
and wide extension of, a purely marine formation, proves a period 
of general subsidence, which possibly was connected with the 
equally wide development of the subsiding movement indicated by 
the north-north-westerly, or Charnian, faults—these, as we have 
seen, having been in part only of post-Cretaceous age. If we can 
add to these arguments that the great uplift was due to activity of 
the Caledonian movement in post-Cretaceous times, the possibility 
suggested by Ramsay becomes a prebability, for it would imply that 
the uplands of South Wales had not come into existence, and 
that there was therefore no obstacle to the advance of the Upper 
Cretaceous sea. I may add that Mr. Jukes-Browne, on a totally 
different line of argument, has concluded that the Upper Chalk 
covered all Wales, except a small area overlying the present Snowdon 
range.” A statement, by which Ramsay was influenced, that no 
trace of Upper Cretaceous rocks exists in South Wales, except for 
some flints in a gravel on the Wye, is not wholly correct, for small 
fragments of flint occur sparingly in the Glacial Drift of South 
Glamorgan. I attach no importance to the fact, however, for they 
may have travelled far. Their great abundance in the ‘raised beach’ 
of parts of Cornwall is more significant. 
Eocene gravels in their turn overlapped the Chalk. Evidence of 
this has been obtained by Mr. Clement Reid in the composition of 
the Bagshot gravels of Dorset,* and recently by Mr. H. B. Woodward 
at Lyme Regis.* Part of the evidence, however, consists in the 
occurrence of pebbles of Oolitic rocks in the gravels; a fact which 
proves that the Chalk had already been denuded, and that the 
uplift in the west had therefore commenced. The inference that the 
limit of the Eocene basin was not far distant receives support from 
the character of the Eocene strata, and the rapidity of the change 
undergone by them in a westerly direction. That they extended 
over South Wales seems scarcely probable. 
1 Quart. Journ. Geol. Soc. vol. xxviii (1872) p. 148. The substance of that 
paper is reproduced in his ‘ Physical Geology & Geography of Great Britain’ 
Gth ed. (edited by H. B. Woodward) 1894, ch. xxxi, pp. 346-66. 
2 «Building of the British Isles’ 1888, p. 194. 
5 Quart. Journ. Geol. Soe. yol. lii (1896) pp. 490-95, & vol. liv (1898) 
pp. 234-88. 
4 Mem. Geol. Sury. Summary of Progress for 1901. (In the press.) 
