J. A. Birds — Geology of the Channel Iskmcls, 113 



Thames as far as Hyde Park.^ These gravels Mr. Trimmer regards 

 as contemporaneous with the rolled gravel and upper erratics of the 

 counties north of the Thames, i.e. of Middle Glacial age. 



Mr. Trimmer again, from the presence of Boulder-clay at Youghal 

 in the South of Ireland, and from grooved and scratched blocks in 

 the south of Co. Kerry, infers that "the South of Ireland was 

 subject to glacio-marine operations ; " and he adds that " the boun- 

 daries which have been assigned to the Boreal Ocean in order to 

 explain the relations of the existing fauna and flora of the British 

 Isles ^ will require considerable modification," that is, as I understand 

 him, an extension further south. 



Again, the same writer quotes from Butter's "Delineation of 

 Somersetshire" (1829) to the effect that "a bed of rolled gravel, 

 associated with the bones of diluvial quadrupeds, was then to be seen 

 at the mouth of the Avon ; " and further, that ridges of sand and 

 shingle "are occasionally found in Somersetshire rising up through 

 alluvial deposits ; " e.g. at Yatton, where a section of these was to 

 be seen in the railway cutting.^ Lastly, Mr. Trimmer has described 

 a bed of gravel on the summit of Clevedon Down, 300 feet above 

 the sea, which he considers to be of Post-Pliocene age. The late 

 Prof. Beete Jukes was, perhaps, deceived as to the existence of 

 glacial markings in the valley of the Exe ; * but Mr. Gr. Maw has 

 pointed out a deposit of what he believes to be Boulder-clay at 

 Fremington, near Barnstaple,^ and he is supported in this opinion 

 by the Kev. W. S. Symonds, who believes that " it may be a glacial 

 Till like that of Bovey Tracey."^ This Till itself again is another 

 argument in favour of the submergence of a considerable portion of 

 the South of England. At Petrockstow, in the centre of Devon- 

 shire, there is said to be an isolated bed of Dartmoor gravel, which 

 has travelled twelve miles from its source. This, too, is identified 

 with the glacial clay of Bovey Tracey. Chalk flints, I believe, are 

 to be found more or fewer on all the coasts of Cornwall and Devon- 

 shire. I have myself found them along the coast of North Devon as 

 well as on Paignton Sands, near Torquay, and under Petit Tor, St. 

 Mary Church, in the south. At Newton Bushel, a few miles north 

 of Torquay, there is a very remarkable deposit of flint-gravel, 100 

 and more feet above the sea, which alone would imply the recent 

 submergence of this part of the country to at least that depth. These 

 flints, as well as some Greensand gravel on the opposite side of the 

 valley, are, apparently, relics of a mass which has floated from the 

 north. So much for the evidences of submergence, of at least a 

 great portion of the South of England, in the intraglacial or intra- 

 continental period. 



What similar evidences may exist of submergence of the north and 

 north-west of France and Belgium I am not prepared to say. Some 



^ Trans. Geol. Soc. vol. v. p. 251. 

 ^ Mem. Geol. Surv. vol. i. plate 7. 

 ' Quart. Joui-n. Geol. Soc. vol. ix. pp. 282-286. 



* Geol. Mag. Vol. II. p. 473, and Geol. Quart. Journ. vol. xxiv. 1838, p. 3. 

 5 Quart. Journ. Geol. Soc. vol. xx. 1864, p. 445. 



* Eecords of the Eocks, by Eev. W. S. Symonds, p. 278. 



DECIDE II. — VOL. V. —NO. III. 8 



