OF NORFOLK AND SUFFOLK. 
115 
THE GREAT EASTERN GLACIER. 
The sketch map (fig. 4) shows the region covered by the 
Chalky boulder-clay, the moraine profonde, as already sug- 
gested. of a great inland glacier which, originating in Teesdale, 
and passing down the Vale of York, moved thence in one 
direction up the valley of the Trent, and in another towards 
the Fenland, having been reinforced by lateral glaciers 
descending from other Pennine valleys, and especially by 
ice which crossed the Chalk Wolds of Lincolnshire, or entered 
through the Humber gap from the North Sea. 
The importance of this inland ice-stream has not been 
sufficiently recognised. Whether we consider, however the 
distance it travelled in various directions, or the area covered 
by its vast moraine, 10,000 square miles in extent, it deserves 
a place in the front rank of the ancient glaciers of Great 
Britain. 
The region covered by the Chalky boulder-clay has a palmate 
outline ; the ice to which it was due having filled the Fenland 
depression to overflowing, radiating thence eastward, south- 
ward, and westward. Its matrix varies with the character 
of the strata over which the ice travelled, being white or 
grey in colour and very chalky in one area, blue and full of 
Kimeridgian shale and septaria in another, while in a third, 
Oxfordian detritus predominates ; in other districts it con- 
tains much material from the Lower Oolite, or the Lias, its 
constant and characteristic feature being, however, the 
presence, generally in great profusion, of the tabular grey 
flint and hard chalk of the Lincolnshire Wolds. In certain 
well-defined areas, Neocomian erratics of a special and 
easily recognisable character, presumably also from 
Lincolnshire, are very abundant. 
As already stated the direct invasion of Norfolk by the 
North Sea ice took place before the arrival of that to which 
the Chalky boulder- clay was due. The latter deposit is 
shown in many places, as for example in the Corton Cliff, 
and at a brick-yard a mile south of Beccles on the London 
Road near the railway crossing, to be underlain by the North 
Sea drift. 
