MIDDLE CEfcALK—SUFFGLIv AND NORFOLK. 
475 
weathering into platy pieces; it is less nodular than usual, but 
Mr. Hill found an echinoderm which appeared to be Galerites 
subrotundus. The lower level showed 4 J feet of similar hard, whitish 
chalk overlying a thin layer of buff-coloured marl and 14 feet of 
whitish Lower Chalk (see p. 213). 
At Sherborne, less than a quarter of a mile north of the church, 
hard yellowish nodular chalk can be seen in a small exposure by 
the roadside, close by an old quarry which is now overgrown and 
talused. This is doubtless the quarry mentioned by Professor 
Barrois, in which he recognised “ the hard nodular bed which 
throughout England occurs at the base of the zone of lnoceramus 
labiatus and which is now called the Melbourn Bock. Erom it 
he obtained the following fossils Am. [ Acanthoceras ] nodosoides, 
Ostrea vesicular is, Inoceramus mytiloides ( =labiatus ), Rhyncho- 
nella Guvieri, and Discoidea minima. 
Whitish nodular chalk is shown in the cutting east of Sedgeford 
station, and what is probably the highest part of the zone in a quarry 
half a mile south-east of Sedgeford, though Dr. Barrois referred the 
latter exposure to the Terebratulina zone. 
The Melbourn Bock is well exposed at the top of the large quarry 
at Heacham, 6 feet of hard yellowish nodular rock, well bedded, but 
weathering into thin, platy pieces along lines and seams of greenish 
marly material. Its base is a well-marked plane, resting directly 
on hard white chalk, without the intervention of any marly layer 
(see p. 213). 
Another good exposure occurs in the quarry north-east of Barret 
Bingstead Farm, and shows the following beds : — 
feet. 
Middle 
Chalk. 
Lower 
Chalk.' 
Hard chalk, broken and rubbly - 
Hard rough creamy white chalk - 
Very hard rough yellowish nodular chalk in two 
„ thick beds (Melbourn Bock) - 
Dull white chalk in thin beds with seams of grey 
marl . 
.Greyish-white chalk in thicker beds 
6 
3 
7 
12 
4 
32 
Rhynchonella Guvieri and Inoceramus mytiloides are common 
in the rough and rocky chalk. 
Terebratulina Zone, 
No exposure of this zone has yet been recorded in Suffolk, south 
of the Lark, though it doubtless occupies a considerable tract of 
country by Kentford, Herrings well, Tuddenham, and Little Barton. 
Mr. H. Woods, of Cambridge, examined some of the exposures 
in the Valley of the Lark during 1901, and has kindly communi¬ 
cated the following notes thereon :—* 
*Becherches sur le Terr. Cret. Sup., p. 16o. 
