MIDDLE CHALK—OXFORD AND BUCKS 
461 
Tlie highest beds of the zone are exposed in Garson’s Lane, 
about a mile E.S.E. of Ipsden House, and not far below 
the outcrop of the Chalk Rock. They consist of tough white 
chalk in solid beds, with a band of soft chalk containing many 
shells of an Inoceramus (probably young I. Cuvieri). 
There is a pit in the middle or higher part of this chalk in the 
combe north of Watlington Hill, and another below Bald Hill 
south-east of Lewknor: both show firm white blocky chalk with 
out flints. Similar chalk has been quarried by the road north-east 
of Kingston Grove and by the side of the London road up Aston 
Hill; these pits have yielded Bpondylus spinosus, Inoceramus 
Cuvieri, Terebratula semiglobosa, and Ventriculites mammillaris. 
There are few good exposures of this zone in Bucks. The beds 
which form a passage between the two zones are exposed in the 
upper level of the quarry on White Hill, near Halt on (see p. 460). 
They consist of rather soft but firm white chalk containing Galer- 
ites subrotundus and large Terebratula semiglobosa. About 
twenty feet are seen, and flints occur rarely; only one small oval 
one was exposed at the time of my visit. 
There are two small exposures near Tring, one about half a 
mile south-east of Tring, and another in the higher part of the 
zone south-east of Aldburv. 
The highest beds of the Terebratulina zone can be seen at several 
places in Oxfordshire and Buckinghamshire where the Chalk 
Rock is exposed. Thus a few feet of it are seen in the quarry 
on Risborough Hill, and some 10 or 12 feet of smooth blocky 
white chalk are exposed in a smaller quarry at a little lower level. 
At Great Missenden nearly 30 feet of this zone are visible below 
the Chalk Rock, the section being 
feet. 
Chalk Rock Beds (for details see Volume III.) - - 11 
White chalk in thick beds - - - - - - -7 
Soft chalk lying between two thin layers of marl 2 
Soft white chalk in thick beds, with a marly layer at the 
bottom..20 
The two thin seams of marl are seen again in the same position 
in a pit east of Havenfield Lodge, north of Missenden, and again 
in a lane leading from Wendover Dean to Bo wood. 
There are also some good exposures in the inlying tract of Middle 
Chalk near Henlev. About 40 feet of solid white chalk in thick 
beds are shown in a large quarry west of Medmenham overlain 
by Chalk Rock. It is also well shown and easily accessible in 
a quarry north of Greenland Lodge on the road to Henley ; here 
at least 30 feet are seen of similar massive chalk without 
flints, but including a thin layer ©f soft marl about 5 feet below 
the Chalk Rock. Mr. Hill, when at the Medmenham quarry 
in 1899, found that this massive chalk was being quarried for 
building material. 
