62 Notes on the Geology of South Ferriby. 
that it was able to divert a huge glacier, twenty miles wide, 
which came down Teesdale from the Lake District. The ice 
from the different areas consequently coalesced, and came down 
the east coast together. The front of the glacier undoubtedly 
formed a formidable barrier, several hundred feet in thickness, 
and as might be expected, it interfered with the normal drainage 
of the land. In this way the waters of the Humber were held 
back, and for a long time there was no outlet for the streams 
feeding the estuary. The result was the formation of a large 
lake. ‘This was first described by the late Prof. Carvill Lewis in 
his book ‘The Glacial Geology of Great Britian.” Lewis gave 
it the name of Lake Humber. 
In accordance with the general behaviour of glaciers and ice 
streams this ancient ice-sheet left a heap of rubbish, known as a 
moraine, at the point where fora time the ice-front halted and 
melted. This rubbish consisted of boulders, pebbles, sand and 
mud, which had been carried along by the ice, some having been 
picked up near the place where it started, whilst more would be 
collected as the glacier proceeded on its way. In yiew of this, an 
examination of the contents of a moraine gives evidence of the 
course the ice took in its travel. 
There is evidence that the ice mass which once filled the 
North Sea and partly covered eastern England, also crept up the 
valley of the Humber. There is also evidence that its wester- 
most limit was reached precisely where Ferriby now is. There is 
certainly no true Boulder-clay with Scandinavian erratics visible 
to the west of this point. 
Boulder-clay is perhaps the most characteristic of all the 
glacial beds. It is usually a tough tenacious deposit, crowded 
with pebbles and boulders of different sorts and sizes, a large pro- 
portion of which are scratched, striated and polished by the 
grinding and moving of the ice. Such a deposit’ occurs on the 
little stretch of foreshore to the west of Ferriby chalk fquarry. 
It is full of striated far-travelled pebbles. On the opposite 
bank of the Humber, at “ Red Cliff,” near North Ferriby, is a 
precisely similar bed. In fact there can be little doubt that the 
two cliffs are the severed ends of a once continuous deposit which 
stretched across the Humber. This was a terminal moraine of 
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