82 REPORT—1868. 
the Cromer coast), overlain by the great Boulder-clay (or Upper Glacial), and at 
West Somerton (seven miles south-east of the Eccles termination of the coast 
section) overlain by Middle Glacial sand, and that again by the great Boulder-clay 
in direct superposition. In its brick-earth condition it is sometimes full of small 
stones, occasionally also of minute chalk fragments, and often contains large sand- 
galls. In the direction of Weybourne this deposit becomes more marly by the in- 
termixture of fine chalk sediment; and west of Mundesley, at which place it 
begins to be contorted, great masses of pure white marl or reconstructed Chalk 
(which have been described as chalk-masses by observers) occur in it, which, by 
the weight of the bergs carrying them, have sunk in some cases into the subjacent 
Till, and even into the Weybourne sand. These marl-masses the authors describe 
as being detached fragments from the more inland portion of the Contorted Drift 
itself; which, inland from the coast, both southwards towards Reepham and 
Holt, and westwards towards Wells, becomes formed exclusively of this mazl. 
They attribute the formation of this marly portion of the Contorted Drift to a dis- 
charge of ground-up Chalk from the débouchure of a glacier that occupied the 
Chalk country of Cambridgeshire and West Suffolk; the brick-earth which forms 
the easterly development of the Contorted Drift being due to a river discharge in 
that part, the two sediments intermingling in the intermediate area, and pro- 
ducing the alternations of marl and brick-earth there preseuted by this formation. 
The detached masses of the marl were, they consider, introduced into the brick- 
earth portion of the deposit by the agency of bergs, which, breaking from the 
glacier and grounding, picked up masses of the marl forming over the sea-bottom 
in that part of the area. These masses the bergs carried out into the area where 
the brick-earth was accumulating, and grounding again, imbedded them in the 
brick-earth, and even in the subjacent Till and Weybourne sand, contorting the 
beds in the process. From detached portions of this marl, which they have found 
as far south as Claydon, near Ipswich, and Stanstead, near Layenham, in Suffolk, 
they infer that this deposit covered the west of Suffolk and Norfolk, but under- 
went great denudation in the former part by the waters of the Middle Glacial seas, 
the sands of that sea, west and south of Diss, lying up to bosses of it in some parts, 
and overlying it in others. 
That the fauna of the Lower Glacial beds is marked by the disappearance of all 
except the boreal and arctic mollusca of the Crag, rather than by the introduction 
of a new fauna, the principal introduction being the Tellina solidula. A list of 
ee species of mollusca was given by the authors from these Lower Glacial 
eds. 
That the sands and gravels, attaining frequently a thickness of fifty or sixty feet, 
which underlie much of the great Boulder-clay in the six counties before men- 
tioned, and which, termed by the authors the Middle Glacial, pass over the Lower 
Glacial series, A,B, C,and p, just described, contain a molluscan fauna, of which they 
enumerate twenty-three species. The interest attaching to this fauna consists in the 
fact that Pectunculus glycimeris, which dies out in the newer part of the Red Crag, 
and is excessively rare in the Fluviomarine or true Norwich Crag, returned during 
this formation in abundance, as well as Ostrea edulis, a shell which similarly dis- 
appears in the newer beds of the Crag, and it is not known now within the Arctic 
circle. Although a bed, a few feet thick, of Boulder-clay identical in composition 
with the great Boulder-clay, but of very limited extent, occurs at the base of this 
formation at two places in north-east Suffolk, and at one place in Hertfordshire, 
its features and fauna both appear to indicate that some considerable amelioration of 
the very severe climate to which the marl of the Contorted Drift that preceded it 
was due, occurred in the interval occupied by this formation. 
That the true widespread Boulder-clay of the east of England, termed by the 
authors the Upper Glacial, ceases from denudation in northern Norfolk, along a 
line drawn from Winterton on the north-east coast to Norwich, and thence passin 
near Aylsham through Cawston, Guestwick, and Barney, to a point a little nort 
of Fakenham. On the east of the county (that is to say, to the south-east of a 
line joining Norwich and Happisburgh) the Middle Glacial sand and the under- 
lying Contorted Drift crop out from beneath the true Boulder-clay in regular 
sequence; but over the centre of Norfolk the authors describe a very anomalous 
