TRANSACTIONS OF THE SECTIONS. 83 
structure, which is that the true Boulder-clay (or Upper Glacial) has been depo- 
sited in a great trough more than twenty miles wide, which has been excavated 
through the Middle Glacial sands and subjacent Lower Glacial beds down to the 
Chalk. The efiect of this has been to bring the true Boulder-clay (or Upper Gla- 
cial), resting on the Chalk, down to a level on the west and south-west of Nor- 
wich, which in some parts is below that of the Crag, and nearly 100 feet below 
the position which it occupies when resting on the older Glacial beds in undis- 
turbed sequence of deposit, the Chalk upon which the Upper Glacial thus rests 
direct being generally in a glaciated or disturbed condition. 
That over the central part of Norfolk, where the Upper Glacial thus goes down 
in solid mass to the Chalk, it is overspread by extensive beds of Postglacial 
gravel*, which not only cap the plateaux, but spread over the sides of the valleys, 
sometimes forming a continuous wrapping sheet down to their bottoms, and pre- 
senting a general absence of terrace structure. These features the authors consider 
as repugnant to any theory accounting for the excavation of the valleys by river- 
action. Similar old Postglacial gravels are also present, but less extensively, in 
eastern Norfolk, where they rest on the denuded surfaces of the Upper and Middle 
Glacial formations; large sheets of them capping the former at HP estagtand, and 
the latter at Mousehold Heath. 
That, in addition to these older gravels, sheets of a newer gravel, more or less 
concealed by the alluvium, occupy the bottoms of most of the river-valleys. This 
newer eravel they consider may be the deposits of rivers during the Postglacial 
period, and after the valleys had been formed by tidal action. 
The sequence of the beds, omitting the Postglacial, may be summed up as fol- 
lows, the beds being taken in descending order :— 
. The Upper Glacial, or true Boulder-clay of the Hast of England. 
. The Middle Glacial sands and gravels. eae 
. The Contorted Drift, beginning as a thin bed in the north-east of Suffolk, Sensi 
and thickening out towards the Norfolk coast. 
. The Pebbly sands and Pebble-beds. 
. The Chillesford Clay. 
. Sands containing the Chillesford shell-bed, or Crag of Chillesford, Sud- True U 
bourn Church Walks, Easton Cliff, and Aldeby, and Upper bed of C S PRS 
Bramerton. soe rane 
7. The Red and Fluviomarine Crag. 
The Weybourn sand (A), the Cromer Till (8), and the indenting sand (c) (which with 
the Contorted Drift make up the Lower Glacial formation) come in below the bed No. 3, 
which spreads over them and over No. 4; but as they are absent where No. 4 is present, 
they, as before explained, may either represent No. 4, or No. 4 may be only the uppermost 
member of the true Crag series. 
In South-east Suffolk No. 2 rests on 5, 6, or 7, but most frequently on No, 7, Nos. 5 
and 6 haying been much denuded prior to the deposit of No. 2. 
Pop Cobre 
BIOLOGY. 
“Address by the Rey. M. J. Burxetry, M.A., F.L.S., President of the Section. 
AFTER alluding to Beker matters that had hitherto prevented him from car- 
rying out his original intention of instituting a course of experiments illustrative 
of the theories which have lately been broached by Dr. Hallier and others respect- 
ing the origin of cholera and some other formidable diseases, the President pro- 
ceeded as follows :— 
Few points are of greater significance than those which touch upon the intimate 
% In the small map of the Glacial beds of the east of England, printed by one of the 
authors for private circulation in 1865, the centre of Norfolk, where these Postglacial 
sands and gravels so extensively occur, was represented as principally occupied by the 
sands and gravels of the Middle Glacial series. This error, which the prosecution of their 
work has detected, the authors desire to call to notice. ae 
