river deposits, to be dredged up by the fishermen of the present time in the North Sea in incredible numbers. Our western seaboard then was probably marked by the hundred-fathom line, sweeping far to the west and north of Ireland, and southwards across the mouth of the Channel. In all probability the geographical conditions of Britain at this time were identical with those of the late Pleistocene (see Fig. 32, p. 150), when our country formed part of the continent.
Early Pleistocene Forests.
The early Pleistocene vegetation covering Britain is represented by the specimens collected by the Rev. S. W. King, in 1861, from the forest bed and lignite beds of the Norfolk shore, and identified by Professor Heer. The forests then growing in the area of the North Sea consisted of Scotch firs, spruces and yews, oaks and birches, with an undergrowth of sloes. In the marshes there were alders, osmund royal, and marsh trefoil; the rivers were gay with the blossoms of the yellow and white water-lilies; and in the pools there were horn- worts and pond weeds. In this list, as Sir Charles Lyell remarks, only one species, the spruce, is not now indigenous in Britain. The history of the arrival of this tree in Europe is very remarkable. Professor Heer, in his description of the fossil plants discovered in Grinnell Land by Captain Fielden, describes the spruce among the Meiocene plants of the Arctic region. "We therefore see that our spruce was living during the Meiocene period in Grinnell Land as well as in North Spitzbergen, and at that time doubtless extended as far as the Pole, at least if any dry land then existed there. In Europe the
