212 
THE CRETACEOUS ROCKS OF BRITAIN. 
The hard white chalk evidently represents the upper and whiter 
portion of the H. subglobosus zone at Cherry Hinton,but here the top 
part is rough, lumpy, and very hard. The overlying marl appears 
to be the attenuated representative of the Belemnite Beds ; it is 
much thinner and its surfaces are less clearly defined than in Cam¬ 
bridgeshire, but it contains that variety of Rhynchonella plicatilis 
which is so commonly found at this horizon. 
A quarry about half a mile south of Barton Bendish exhibits a simi¬ 
lar section as above, and there is a good exposure of the same beds 
at Mar ham limekiln, where the following section was seen by us 
in 1886 (Op. cit. p. 567) : — 
ft. 
Thin soil and weathered Melbonrn Rock - - 5 
Band of yellow marly chalk, with a layer of grey marl at the 
base ------ _ _ . . ii 
Hard white chalk, weathering rough and projecting over 
the face below --------- 9 
Blocky greyish chalk - - - - - - - - 10 
About 25 
At the north corner there is a marked layer of nodular rock at 
the base of the hard white chalk, but it is not continuous. A similar 
section is shown in the pit south-east of the church. 
A little north of the first quarry are two cottages, and we were 
informed by the Rev. H. J. Sharpe, Vicar of Marham, that a well 
was sunk here to a depth of 85 feet, clay being reached at that 
depth and bored into for 30 feet. As the cottages are very little 
below the outcrop of the Melbourn Rock we may estimate the 
thickness of the Lower Chalk here at about 90 feet, which is about 
40 feet less than its probable thickness near Stoke Ferry. 
A quarry at Gayton, N.N. W. of the church, is worked in two levels 
and exposes about 46 feet of the zone of Holastcr subglobosus , the 
section being as follows : — 
Upper Level. 
ft. 
Soil and rubble --------- 1 
Dull white chalk, rather tough, weathering into platy pieces 20 
Lower Level. 
Firm white chalk in thicker beds - - - - - - 12 
Hard chalk, parting along greenish marly seams 2^ 
Greyish marly chalk in massive beds - - - - - 12 
Mr. Whitaker says of this pit that “ its great interest lies in the 
fact that small boulders of granitic, gneissose, and trap rocks are 
found in the chalk. . . . There were in 1882 a few large pebbles, 
up to 9 inches in length, lying in the pit. These are said to be 
found in the chalk at some depth, and there is certainly no other 
apparent source for them, the Chalk being quite bare [of Drift] . . . 
I took away one, and on a later visit several others, which are now 
in the Jermyn Street Museum/’* 
* The Geology of South-Western Norfolk, Explanation of Sheet 65, 
Mem. Geol. Survey, p. 35, 1893, 
