544 S. V. Woodjjun. — American and British Surface-Geology. 
that south of Mappleton, wliere the uppermost part of the purple 
clay has escaped the denudation which, prior to the Hessle beds, 
destroyed it elsewhere to the south of Bridlington, the rapid decrease 
of the chalk debris is very marked, but the decrease of the debris of 
the hard rocks north of the Wold is much less conspicuous. Still, 
even this diminishes, and though it continues in the clay of the 
upper parts of these two cliffs, it becomes so scant that in the 
uppermost part wliere the chalk debris has wholly ceased, and 
wliere the Hessle clay with its subangular chalk debris wraps over 
it, there is ver} r little debris of any kind in the clay. It is in fact 
a stiff mud, much resembling, save that itis stiffer and uncontorted, 
and has no chalky Sediment intermixed in it, the Contorted Drift of 
Cromer Cliff, which is generally conceded to be a marine silt, though 
nearly destitute of organic remains. It is. I think, more than doubt- 
ful whether any of the clay without chalk south of the Pickering 
trougk is of direct morainic origin, either as originally extruded, or 
as dropped. It seems to me, though produced from the grinding 
of the glacier-ice, to liave been distributed by marine agency, ac- 
companied by the dropping of erratics from floe-ice ; for not only 
is this clay full, though at no particular horizon, of lenticular beds 
of sand (c and d! of Section I.) — a feature which the true morainic 
chalky clay of East Anglia lacks — but it presents the most marked 
contrast to the small moraines of pure rolled chalk (c of the same 
section) which underlie it, and occupy ravines or gullies in the chalk 
floor where it rises above the beach from Bridlington northwards. 
These small moraines are evidently connected with the purple clay 
containing much chalk of the cliffs south of Mappleton (c of the 
section), the place of which they occupy relatively to the clay with 
little and no chalk ( d ) that overlies both ; and baving been formed 
beneath the Pickering glacier while it still rested on the north- 
eastern extremity of the Wold after the termination of the chalky 
clay formation, they seem confinnatory of the mode in which the re- 
treat of the ice took place, as indicated by the other phenomena 
previously discussed. 
As this mud-like clay (d) caps the cliffs continuously northwards 
from Bridlington to the mouth of the Pickering trougk (which it 
blocks up), and for several miles attains elevations between 350 and 
400 feet, it seems to me to indicate that when the Pickering glacier 
by shrinking back gave rise to its accumulation, Torkshire must 
kave been submerged to that extent. 
The recession of this glacier through the Yale of Pickering after 
the disappearance of the glacier which produced the chalky clay is 
thus, it seems to me, very clearly indicated ; as well as two corol- 
laries ; the first of which is that, when the chalky clay was in pro- 
gress of accumulation, the contemporaneous moraine that passed 
through the Yale of Pickering was left out in the sea beyond our 
present shores ; and the second of which is that, since the further 
north the latitude the later must kave been the recession, the 
Glacial clay of the northernmost English counties is later than all 
this of Hoiderness, except possibly that which, wholly destitute of 
