Clement Reid—Glacial Deposits of Cromer. 65 
about doubled in thickness, but the absence of inland sections 
prevents any further estimates being made. 
Inland exposures of Contorted Drift—If the explanation above 
advanced as to the date and mode of formation of the contortions be 
correct, it is evident that it ought also to account for the contorted 
beds near Norwich and in the Waveney Valley. 
Before examining the coast section I mapped a considerable 
district in the Waveney Valley, on the borders of Norfolk and 
Suffolk. While engaged in this country I was constantly puzzled 
to find that where the Lower Boulder-clay was contorted, it was 
always directly overlaid by the Chalky Boulder-clay; but where un- 
contorted, the two were commonly separated by the undisturbed 
Middle Glacial Sands. If Iam correct in referring the contortions 
to the age of the Great Chalky Boulder-clay, it is evident that this 
is just what we ought to expect; but on the theory that the contor- 
tions are contemporaneous with the bed, it is a most extraordinary 
coincidence. In the Norwich district, also, my colleague, Mr. H. B. 
Woodward, has found that all the large disturbances can be referred 
to the period of the Chalky Boulder-clay. 
This, I think, will much simplify East Anglian geology, as it now 
appears that all the large disturbances are referable to one period— 
that of maximum glaciation, or of the Chalky Boulder-clay.' 
Summary and General Conclusions.—The changes that have taken 
place since the close of the Pliocene epoch may be thus summed up, 
commencing at the oldest deposit :— 
Arctic Freshwater Bed, with Salix polaris, Betula nana, etc. 
First Till.—Advance of the ice descending from the chalk escarp- 
ment, and ploughing out sand-banks and marine boulder-clays of the 
Wash. 
Intermediate Beds.—The ice recedes a few miles, and glacier-mud 
is deposited as ripple-marked loams and marls on the hummocky 
surface of the First Till. 
Second Till.—Ice again advances, forming a second deposit of 
unstratified till. 
Sands.—Submergence and formation of fine false-bedded sands. 
Contorted Drift.—Strongly but irregularly bedded boulder-clay, 
probably sedimentary. 
Bedded Sands and Marls.—Classed with the Contorted Drift. 
Middle Glacial? Sands and gravels, resting on a slightly eroded 
surface of the Contorted Drift—not in valleys, as stated by Messrs. 
Wood and Harmer. 
Chalky Boulder-clay.—Represented by the chalk and marl masses 
near Cromer, and by a ground-moraine sometimes formed at the 
base of the Contorted Beds. The large contortions are all of this date. 
The period from the Chalky Boulder-clay to the present time 
seems also to be well represented in the Cromer Cliffs, but as the 
later glaciations did not extend so far south, the Boulder-clays of 
1 See also, with regard to the similar large disturbances in the Island of Moen, 
now proved to be of Glacial origin, Johnstrup, in Zeitschrift der Deutschen Geol. 
Gesellschaft, 1874, p. 583. 
DECADE II.— VOL, VII.—NO. II. . b) 
