File:The Quarterly journal of the Geological Society of London (12733864315).jpg

THAKET BEDS AND CRAG AT ST7DBURY, SUEEOLK. 403
river, laying bare the set of beds shown in the figure, drawn on the
same scale as various analogous figures in the Memoir on the
London Basin*.
No fossils have been found in the beds that I have classed as
Thanet Sand, except some pieces of Foraminifera, by Dr. Holden

the reasons for this classification are purely lithological, and as
follows

—
1. The likeness of the sand, in fineness, compactness, and colour
to that which occurs in the same position in "West Kent.
2. The persistence of these characters in all the sections, and the
absence of false-bedding of pebbles and of red-mottling, tending to
show that the sand belongs to tbe Thanet Beds rather than to the
more varying Reading Series.
3. The fact that the greensand at the bottom is like the " base-
bed " of the Thanet Sand

and the occurrence immediately beneath
it of a layer of tabular flint, as is very usual where that bed caps
the Chalk.
"Westward from Sudbury I have traced this sand for more than
three miles

but eastward it is soon hidden by Drift, after being
shown in many sections on the outskirts of the town. The green-
sand over the Chalk, near Ipswich, is much like that at Sudbury

so perhaps the progress of the Geological Survey may establish the
occurrence of the Thanet Beds in that direction.
In the northern band here noticed this division seems to be pre-
sent at the expense of the overlying Beading Beds, which are re-
markably thin at Sudbury; and this outcrop most likely joins on
underground to that in South Essex and Kent, many of the deep wells
in the tract between seeming to pass through the Thanet Sand.
2. Crag.
The pits that give evidence of the occurrence of Crag have been
opened only during the last few years, and are all on the left, or
Suffolk, side of the Stour, at the northern and eastern edge of Sud-
bury, the three best sections being close together, on the hill within
a quarter of a mile N.E. of St. Peter's Church.
The general section of these is as follows

—
A small patch of Drift.
Crag. Ferruginous dark reddish -brown sand, -with layers of ironstone, slightly
false-bedded

in parts a light-coloured grit with broken shells

thin layers of flint-pebbles, phosphatic nodules, and phosphatized
bones in the lower part

and at the bottom a marked bed of the same,
up to a foot or more thick. The whole as much as 10 feet in a hol-
low, elsewhere as much as 7 feet.
Thanet Sand

the lower pinkish bed, and the green base-bed.
Chalk.
In the furthest pit, Mr. "Webb's, the shells are mostly broken up,
and many specimens of Purpura lapillus, var. crispata, with one
valve of a small Anomia ephijppiurn, were all that could be found in
any thing like a perfect state

but in the nearest pit, Mr. Harding's,

Memoirs of the Geological Survey, iv.