294 
MR. CLEMENT REID ON EAST NORFOLK GEOLOGY. 
thickness. No trace of the freshwater clay with temperate plants 
was observed in the spoil heap ; but this bed at Mundesley is quite 
local, and never more than a foot in thickness. 
The Chillesford Clay (seen during the next visit) was like that 
bored into on the foreshore to a depth of twenty-two feet in 1892 
(all Pliocene deposits tend to thicken towards the North Sea). The 
occurrence in it of Scrobicularia piperata and Hydrobia idvce is 
sufficient to prove its estuarine origin ; but the shells are extremely 
rotten, and I could find no foraminifera or other microscopic 
organisms. The gravel below is obviously the equivalent of the 
gravelly Crag of Weybourn and Runton, here more estuarine, 
though perhaps deposited in deeper water. Fragments of thin- 
shelled Tell inn halthic.a were fairly abundant in the spoil-heap 
where the material from immediately above the Chalk had been 
placed; but I could find no other of the characteristic Weybourn 
Crag species, though they are known to occur at Trimingham and 
North Walsham. 
The character of the Chalk met with in the Mundesley Well 
settles a doubtful point in Norfolk geology. It has long been 
known that the Chalk of Trimingham was probably the highest in 
England, and recent work lias shown that it belongs to a division 
(zone of Ostrea lunata and Thecidium vermicular e), unknown 
elsewhere in this country, and containing fossils peculiar to high 
beds on the Continent. A doubt, however, has arisen as to the 
Trimingham Chalk; for it is everywhere disturbed and raised by 
glacial action, and in several places boulder clay can be seen to 
pass beneath it. This suggests that the whole mass may be nothing 
but an enormous boulder transported from some other region. In 
the Mundesley Well, however, there is no such doubt, for undis- 
turbed Chalk is there overlain by various stratified preglacial 
deposits. It is interesting therefore to find that this Chalk is like 
that of Trimingham, and contains, in abundance, the same peculiar 
oyster for the first sixty-one feet at any rate, and the same peculiar 
cavernous flints throughout. Unfortunately, the specimens of Chalk 
saved for me contained no other fossils, and I found, on my last 
visit, that all the rest of the Chalk had been carted away and 
placed under the floor of a barn — where, perhaps, it may be got at 
by some geologist in the future. 
