73 



Britain, was not less than 5,000 feet. The centre of dispersion was 

 the table-land of Scandinavia. A second centre was the Scottish 

 Highlands, and a third the interior of Ireland. — 10. 



The peculiar syenite of Laurvig, in the south of Norway, has 

 been found in the boulder-clay of Yorkshire. I have myself found 

 it in Lincolnshire. 



When the ice-sheet melted, the escaping water would at first 

 flow with little relation to the present main drainage lines. Streams 

 would be let loose over the plateau and hilly ridges, as well as over 

 the plains. To this kind of action may be attributed the masses of 

 gravel and sand which, over so much of northern Europe, rest on 

 boulder-clay — sheets of plateau gravel, and mounds and ridges of 

 sand. — 11. 



In this country the terminal moraine of the Norse ice-sheet is 

 the range of gravel hills stretching from Flamboro' Head across 

 Holderness and on into Lincolnshire. — 12. 



In the Isle of Man, the phenomena show that at one part of 

 the glacial period the Irish Sea-basin was filled with an ice-sheet 

 thick enough to over-ride the highest summits, 2,000 feet, of the 

 Island. — 13. 



Dr. Hicks has carefully examined the proofs of ice-action 

 in N. W. Pembrokeshire. The presence of erratics from North 

 Wales and from Ireland led him to the conclusion that glaciers 

 from those areas coalesced in St. George's Channel, and that the ice 

 which overspread Pembrokeshire was derived from both those 

 sources, as well, probably, as from a flow extending down the 

 channel from more northern areas. 



By N. W T . Pembrokeshire he means the whole of that portion 

 west of a line drawn from Fishguard on the north, to Haverfordwest 

 on the south. East of this line the ground rises towards the 

 Preselly range of mountains in N. E. Pembrokeshire, which was 

 outside the district in review, a district which included St. David's 

 Head. Here, the highest peaks attain to an altitude of about 600 feet,, 

 and the evidences of glaciation, even at the present time, are quite 

 clear up to 400 feet, though the ice probably covered them all. It crept 

 across the ground from a north-westerly or seaward direction, and 

 bore with it fragments of flint and boulders of granite. 



Across St. David's Head the striae ran from W.N.W. to 

 E.S.E. Ramsey Island carries transported materials on its two 

 main crags, of which the highest is 446 feet. The thickness of 

 the ice-sheet could not have been less than 800 feet to 1,000 feet, 

 and may have been much move. — 14. 



Much more it certainly was. The Preselly Mountains are 

 seven miles long and two broad. Cwm Cerwyn, their highest 

 point, is 1,760 feet above O.D. Gower and even the Devonshire 

 coast can be seen from it, and at that altitude, in 1899, I found 

 these erratics — an igneous rock and a granitoid. The mountain 



10 — Geikie. Text-book of Geology, 2nd Ed. 



11 — Geikie. 

 12 — Thos. Sheppard. Glac. Mag., iii., 129. 

 13 — Lamplugh. Glac. Mag., v., 73. 

 14 — Glac. Mag., i., 191. 



