Dr. D. Woolacott—The Interglacial Problem. 69 
‘Disappearance of ice from counties. 
Retreat of ice from country until small glaciers occupied 
valleys in Cheviots and Lake District, etc. 
Final retreat of Tweed—Cheviot ice from coastal region. 
Deposition of leafy clays, etc., in the Tyne and Tees 
valleys in lakes held up by ice along coastal border. 
Formation of glacier-lakes in Mid-Northumberland and 
of associated Kaims and overflow valleys, when the 
Western ice had retreated and the Tweed-Cheviot still 
occupied the coastal border; concurrent formation of 
lakes in lower Teesdale and Weardale; cutting of 
Ferryhill Gap; commencement of erosion of gorges 
of Wear, Wansbeck, etc., by streams flowing from 
waters held up by ice. 
Formation of Grindon, Warden Law, and Sheraton Kaims 
on the margin of the Tweed-Cheviot ice occupying the 
coastal region of Durham. 
Glacier-lakes of Cleveland Hills formed during maximum 
Glacial. pressure of the combined ice-sheets along the coastal 
region. 
Glacier-lakes formed in the higher regions of Teesdale, 
Weardale, and the Cheviots. 
Advance of Forth and Tweed-Cheviot ice and of Western 
ice across Northumberland and down Teesdale; all 
these streams were diverted southwards by the pressure 
of the Scandinavian ice-sheet.* 
Possible Interval in Glaciation. 
Advance of Western ice across coastal region. 
Possible Interval in Glaciation. Possible formation of 
Horsebridge Head gravels as an Interval-depostt. 
Advance of ice from Scotland along coast of Northumber- 
land.? 
Glaciation-Interval. (Possible  Interglacial Pervod, 
Trechmann.) Formation of Interval deposit of loess, 
etc. Possible formation of Interval shore-deposits and 
erosion of valleys. 
| Advance of Scandinavian ice-sheet to Durham coast.? 
Deposition of Teglian, Cromerian, and other deposits on 
the North Sea area. 
Formation of Preglacial valleys of ‘‘ Wash’, “ Tyne”’, 
“Tees ’', etc. , 
Pre-Scandinavian 
Drift * or 
Preglacial. 
1 and® If Interglacial Periods did not occur, then the Scandinavian ice must 
have occupied the North Sea area continuously during the glaciation of the two 
north-eastern counties. It was the first to reach the Durham coast, and the 
Tweed—Cheviot ice was held along this region by it until the retreat of the British 
ice had commenced. The Sewerby Raised Beach, the Horsebridge Head 
deposit, as well as the Interval-deposits given, may have been formed between 
2and 4. The Basement Clay of Holderness, if, as already suggested, it is not 
contemporaneous with the Durham Scandinavian Drift, may have been deposited 
and the Bridlington Crag also pushed inland in the period between 2and4. The 
Kelsey Hill deposits were probably carried inland at the same time as the 
Durham Kaims of Grindon, Warden Law, and Sheraton were formed. 
2 As already stated there is evidence for an advance of ice from Scotland 
ane the coastal region of Northumberland before the western ice occupied 
the area. 
4 On the hypothesis that there was an Interglacial period before the 
Scandinavian ice reached England; if only a Glaciation-Interval, then Pre- 
glacial as far as North-East England is concerned. 
