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deposit did not present the highly inclined bedding of the Red Crag since it seems
to have been laid down under different conditions, probably as the western edge of
a large delta of the proto-Rhine. It attained a much greater thickness in the subsoil
of Holland where it was deposited in a subsiding area with the subsidence dying
out towards the west.
3.3.4 The Chillesford and Cromer Forest Beds,
and Weybourne Crag
The next deposits in the geological succession, the Chillesford Beds, overlie the
Red and Norwich Crags and appear to be related to the probable course of a proto-
Rhine estuary with its exposures of laminated micaceous sand and clay. It is
suggested that at two subsequent stages of the late Tertiary, evidence of similar
conditions found in the estuarine clays and gravels of the Cromer Forest Bed series
containing fossil remains of the Southern Mammoth (Elephas meridionalis), also
indicate a northward outlet of the proto-Rhine, while in the submerged North Sea
deposits the remains of many land animals, such the Northern Mammoth (Elephas
primgenious) have been dredged from Dogger Bank. Unlike molluscs, these are
fossils of extinct species and whilst the mixture of southern and northern forms
may indicate changes of climate due to the oncoming cold conditions, there is the
Fig. 3.13 P680260 (1907) Harmer's geological excursion to Norfolk. Cliffs at Runton, Norfolk
coast with Cromer Forest Bed deposits at the cliff base. (CP13/050 Reproduced by permission of
the British Geological Survey NERC. All rights reserved)
