XX SUPPLEMENT TO THE CRAG MOLLUSCA. 
In tracing this drift from the Hast coast at Hopton, and from the numerous inland 
sections of the extreme North of Suffolk and East of Norfolk, towards the Cromer coast, we 
see it in a fine section at West Somerton, overlain by the sand, No. 8, which is again close 
at hand overlain by the clay, No. 9 (see Section M), and we then lose it by the interven- 
tion of several miles of marsh. On the cliff beginning to rise at Eccles the drift appears 
again in the identical form of reddish-brown brick-earth possessed by it at Somerton, but 
overlain by a thin bed of stony clay (No. XI), to be presently noticed. From this place 
westwards it can be seen to assume gradually the finely stratified appearance it possesses 
at Hasboro’, and then to change still further west into its original red Brick-earth 
condition. 
This deposit must once have spread far to the southward, for what appear to be 
outliers of it occur at Kesgrave (five miles south-west of Woodbridge), and at Blaxhall, 
half a mile east-north-east of the church (seven miles north-east of Woodbridge) ; while 
beyond the limits of the map we have found it in the south-west of Suffolk, near 
Boxford, and probably at Sudbury. The Blaxhall outlier contams marl masses similar 
to those in the North Norfolk coast section. 
The breaking off of this deposit into outliers southward is evidently due to a great 
denudation of the Lower Glacial formation prior to the accumulation of the Middle 
Glacial sands, which occupy to a great extent troughs or valleys in the Lower 
Glacial beds; and it is quite possible that outliers of it may be concealed under the 
tablelands of Middle Glacial sand which separate the Hast Anglian valleys from each 
other in Section A. It is clear that the valley system of Hast Anglia had its inception in 
this denudation, though it would be beyond the scope of the present outline to show this 
further than appears from the sections accompanying the map.’ 
The Contorted Drift has yielded no fauna as yet worth mentioning; but Zellina 
Balthica and fragments of Cardium edule, Cyprina islandica, and Mactra ovaiis, and of a 
Mya, are not unfrequent in it. We took from it at Elsing (twelve miles west-north-west 
of Norwich) the femur of a small mammal. 
Toe Mippite Guacrat (No. 8). 
This formation is principally composed of sand within the limits of the map, though 
gravel is more or less intermixed in places; but southwards, towards and over Essex, the 
formation consists mainly of gravel. These sands have their greatest thickness over the 
Red Crag region, and were Jong confounded with that formation, under the term “un- 
productive sands of the Crag.’ Although the sands over the Crag are treated by usas all 
1 We should explain, however, that it is to this intraglacial erosion that the chalky clay (No. 9) owes 
its abnormal position in the bottoms of valleys cut through the older Glacial beds—a position which, before 
we had discovered the true explanation of it, led us to suppose (as suggested in vol. xxiii of the ‘ Quarterly 
Journal of the Geological Society,’ p. 89) that the clay in the valley bottoms was a different Boulder clay of 
subsequent origin to the clay No. 9. 
