1894-95] ^9 



Age." Thirty or forty years ago it was universally considered 



that it was coincident with a great submergence of the land — 



perhaps to nearly 2,000 feet below the present level — and that 



a sea loaded with icebergs, drifting generally from north-east to 



south-west, had deposited the clay and boulders, much as is now 



being done between the mouth of Davis Straits and the Banks 



of Newfoundland, and that the polished and striated rocks 



which underlay the clay were due to the grounding of these 



wind and tide driven icebergs upon the shore. The ingenious 



author of " Frost and Fire," a charming book to read by the 



way, published nearly thirty years ago, gives a map showing 



the British Islands submerged 2,000 feet, with channels where 



several Scottish rivers now run, through which these icebergs 



were supposed to have come drifting from Scandinavia, The 



high ground not submerged had local glaciers that helped to 



swell the number of icebergs, which glaciers as the climate 



moderated shrunk up, leaving moraines and ice-worn valleys 



behind them. At the height of the glacial period, according to 



this theory, Scandinavia was covered by a vast sheet of ice to 



even a greater extent than Greenland is now, because the ice 



stretched so far out into the bed of the North sea as to infringe 



upon the coast of Great Britain and to meet and coalesce with 



a great sheet which enveloped the whole of Scotland, which 



sheet in its turn spread westward so as to glaciate the outer 



Hebrides, and southwards so as to fill up the Irish Sea. Here 



on its south-east side it flowed round and met with an ice field 



which covered the mountains of Cumberland and Westmoreland, 



and reinforced by this, pushed its way through various gaps in 



the Pennine range— the " backbone of England" — till it died 



away in the plains of Yorkshire and Durham and the Midland 



counties. Upon its south-western side it also met with another 



great mass of ice, which probably had its centre over the 



Sperrin Mountains in North Tyrone and South Derry, the two 



masses or streams meeting in Antrim and Down, where they 



breasted up against and partly over-rode the Mourne Mountains. 



There were also local icefields of considerable extent in Wales, 



3 



