104 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ Dec. 8, 
wards beyond Leicester—whereas the chalky clay extends to the 
southern parts of Essex and Middlesex*, and the sea depositing it 
extended still further, as is proved by the way in which the clay is 
cut off from denudation at elevations reaching up to 350 feet on the 
northern brow of the Thames valley; but to what distance it may 
have gone, the denudation has been too complete in that direction to 
justify an assertion, though, from the structure of the Thames gravel, 
T believe it to have stretched beyond the limits of England. 
The long triple section, No. 3, traverses the entire length of this 
elay from its southern termination to its overlie in Holderness by the 
purple clay with chalk, and thence to the purple clay without chalk, 
which begins about Flamborough, and, crossing one of the lowest 
parts of the dividing ridge at Stainmoor, terminates at the West- 
moreland Fells. The upper representation of this triple section 
is drawn to the existing sea-level, and shows, as nearly as the 
small scale will allow, the relative elevations along the line taken, 
the older formations forming the floor of the deposit, and the dis- 
tribution of the clays in question along the line taken. The Lower 
Glacial series (which together forms a separate and unconformable 
deposit) lies to the east of the line of section taken, and may be 
altogether omitted from consideration in this question. The Middle 
Glacial, although it was a deposit formed under a marine climate 
very different from that obtaining at the time of the chalky clay 
which overlies it, yet appears to have been a deposit formed du- 
ring the commencement of the submergence under which the chalky 
clay was accumulated, since in many parts it passes up by inter- 
bedding into that clay. Features in its structure and position, which 
I hope to enter upon in detail on a future occasion, indicate, more- 
over, as it seems to me, that although the marine climate was so 
different from that obtaining when the chalky clay was deposited 
as to have permitted neither the formation of Boulder-clayf nor 
the transport of rock-boulders, yet the land was occupied with ice 
in places which were afterwards covered deep below the chalky 
clay, these places being far south of the ice-limit indicated in the 
outline map. ‘The line of section crosses this deposit at one part 
only, the bulk of it lying to the east of the line, though a consider- 
able development of it also occurs to the west of it. 
The middle representation of this triple section indicates what 
I conceive to be the conditions obtaining when the deposit of the 
chalky clay was taking place. This representation supposes a de- 
pression of from 600 to 700 feet below the present level, and it shows 
this clay as forming southwards from the foot of the ice-sheet on 
the western side of the Lincolnshire Wold, and supplied by material 
* The purple clay with chalk forms a belt im Holderness and East Lincoln- 
shire that overlaps a little the unshaded part, and also overlies there the chalky 
clay which the shading represents. See sections 1, 5, and 11 of the paper of Mr. 
Rome and myself (Quart. Journ. Geol. Soc. vol. xxiv. pp. 148, 160, and 169.) 
+ A band of Boulder-clay (chalky) does occur in the Middle Glacial gravels 
at one or two localities, and serves as an exception to prove the truth of this 
rule. 
