HARMER : FIELD EXCURSION TO CROMER, ETC. 313 
this fact, which is both interesting and important, I can offer 
no other explanation than that suggested by Wood in 1880,* 
that the Chalky Boulder-clay of the region in question originated 
as a great mud bank, at first driven before or dragged along 
by the advancing ice, and afterwards over-ridden by it. 
The relation of the three local divisions of the East Anglian 
drifts proposed by Wood was arrived at by the mapping of the 
region hang between Yarmouth and Lowestoft, and that of the 
Flegg Hundred (Fig. 2) to the N. of Yarmouth, in the years 
1868-70, and was seen in an interesting exposure at Gorton, to 
the N. of Lowestoft, visited during this day's excursion, where 
the Chalky Boulder-clay, the Middle Glacial sand, and the Lower 
Glacial brickearth, the latter containing igneous erratics, were 
shown in continuous section. f 
Attention was drawn to the ravages of sea upon the coast 
immediately to the south of Lowestoft harbour. Taking ad- 
vantage of the fact that there is here a prevalent travel of the 
beach from north to south, groynes are constructed for the 
purpose of arresting this movement, but unfortunately pro- 
tection to one locality must always be gained at the expense of 
another. 
An illustration of this is afforded by the harbour works at 
that place, which have caused a vast and unnecessary accumula- 
tion of sand to the north of that place, while the cliffs to the 
south, robbed of their only reliable defence, are being rapidly 
destroyed by the sea. Groynes cannot create beach, they can 
only arrest its natural movement. Nevertheless thousands of 
pounds are being thrown into the sea near this spot year by year, 
in the construction of such works, where they can do but little 
good, and are sometimes swept away almost before they are 
completed. 
On Tuesday, July 14:th, a visit was paid to Forncett, nine 
miles to the S. of Norwich, where the railway cutting already 
*Quar. Jour. Geol. Soc, Vol. xxxvi., p. 487, 1880. 
t [There are some facts, however, which seem to indicate that a portion 
of the Contorted Drift may possibly be contemporaneous with the Chalky 
Boulder-clay. The author hopes to deal more fully with this part of the 
subject in a future paper.] 
