Page:Quarterly Journal of the Geological Society of London, vol. 29.djvu/277

 was glacier-ice at first, grounded in 1800 feet of salt water ; at 3000 feet, in 2700 feet or 450 fathoms, according to measurements which I made off Labrador on ice from a stranded berg. The general southerly movement was turned aside locally. At some time there was movement in a south-westerly direction from the Baltic by way of Gotheborg and across Scotland by way of the Forth and Clyde, and apparently across Ireland also. There was a wide and extensive movement south-eastwards from the east of Scandinavia down by the course of all the Swedish rivers, and over Finland past St. Petersburg. On the northern shore of the gulf of Finland marks upon granite indicate very thick ice moving over a wide area. There have been a succession of movements. When each glacial period was at the greatest, and climate began to warm up, each great mountain system in a low latitude separated from the crust and became a separate centre of movement. The general system has now shrunk far within the -arctic circle; but Spitzbergen, Iceland, Greenland, patches in Scandinavia, and in the Alps, still are gathering-grounds for snow and bases for local systems of glacial action. All these were larger by far. That at least is certain. There can be no question about the enormous extension of the alpine ice-system, and of the transport of stones by ice from the Alps far northwards into the plains of Germany, and far southwards into the plains of Lombardy.

To see Norway and Sweden is to understand that the whole area was one great sheet of glacier-ice moving far out to sea on the N.W., and far out into the low grounds of Europe on the S.E. A former great extension of glacier-ice from existing centres is proved.

The next problem is to make out whether the Scandinavian and Alpine systems met in the low grounds of Europe, and there joined the general Polar system ; and if so, how far and to what latitudes this general compound system of glacial movement extended, how it moved, and what work it did. I believe that the general movement and the united crust of ice once reached as far as Washington in America, and as far south as Greece on this side of the Atlantic, and probably united east and west round the world. The leaders of the vanguard teach, as I understand them, that the crust reached nearly to the equator.

XIX. Ireland. — The later record in Ireland now seems to read thus. From Kerry to the White Sea there was a continuous ice- system of vast mechanical power, which has gradually retired northwards. As it retired it broke up into separate local systems ; as the main system retired northwards from them, the local systems retired from the sea and from the plains up the hills. As the plane of perpetual snow rose from the plane of the sea above the highest hills in Ireland, the Irish local ice-systems also rose till there was no base left for snow to rest on. That which I have seen of late is the record upon the surface of Ireland, the shape of which I attribute chiefly to glacial action, as I have said.

XX. Under water.— As I now read marks in Kerry and on the Scotch and Norwegian coasts, ice during the last glacial period