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Professor Hughes, The Gravels of East Anglia 147 
The Gravels of Hast Anglia. By Professor HUGHES. 
[Read 25 November 1912.] 
In introducing the subject of the gravels of Hast Anglia the 
author pointed out that too much importance must not be attached 
to the absolute height and level of the river terraces, firstly because 
of the rise of the valley from its mouth to its source and secondly 
on account of the earth movements which have affected the area. 
He showed that there had been considerable depressions in the 
_yalley of the Cam since the deposition of some of the existing river 
silt. 
Only a small proportion of the flints of which the gravels were 
chiefly composed were likely to have been derived directly from 
the Chalk and very few from the London Tertiaries. They were 
probably produced on the Miocene land surface over which the 
Crag sea advanced rapidly sweeping up the old surface soils and 
_ forming the first deposits of angular flints from which so much of 
our stained gravel has been derived. 
The subsequent depression of this area, while adjoining moun- 
tain regions were uplifted, would account for the material of the 
Norfolk cliffs which might be referred to the action of an ice-laden 
sea on the land. Shore ice and pack ice early impinged upon the 
sinking and afterwards the rising land, mixing up and contorting 
the material upon it, and creeping up the long slopes and over the 
_ wide plains with similar results. 
He traced these glacially formed or glacially modified beds 
from the coast to the hills inland, pointing out that every character 
which was seen in isolated sections inland could be seen along the 
coast in continuous sections. They differed from the river gravels 
in their tumultuous arrangement and in their great variety of 
composition. 
This group, of glacial origin, were well represented by the 
~ Whittlesford beds. 
The loam of the cutting near Chesterford Station, and the 
sands, gravels, loam and marl of Hildersham, Gog Magogs and 
Hare Park were assigned to the same series, and connected with 
the coast by the deposits of Roslyn Pit, Sedgeford and Hunstanton. 
As the land rose the agents of subaerial denudation began their 
work at once and the rain-wash and river-terraces thus formed, 
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