MIDDLE CHALK—OXFORD AND BUCKS. 
459 
London (1889, p. 66). These consist of solid and massive chalk, 
which near the top passes up into harder and rougher nodular 
chalk. 
Stratiqraphical Details. 
Zone of Rhynchonella Cuvieri. 
Part of this zone is exposed in an old pit about 30 feet deep by 
the side of the Thames at Goring, but is much weathered. The 
looser parts are decomposed into rubbly yellowish chalk, while 
lenticular masses of hard, shelly chalk project from the face of the 
pit. Rhynchonella Cuvieri and Inoceramus mytiloides are common; 
Cidaris dissimilis (a test), Calerites subrotundus, and Terebratulina 
gracilis var. lata were also found. Similar chalk, but in more 
massive beds, very hard and resembling the top of the Melbourn 
Bock, occur at the level of the water near Cleeve Mill. 
At the north end of the Temple grounds, where one would 
expect to find still lower beds, there is a quarry which appears 
to show the junction of this zone with that of Terebratulina , viz. : — 
feet. 
Soil and rubble - - • - - - - - - - 2-4 
Soft white chalk with finger-like flints ----- 8 
Hard rocky yellowish chalk with Inoceramus mytiloides - 1CH14 
About 24 
Between this and Watlington there are no good sections, but 
a quarry east of Watlington Harm shows the greater part of 
the zone ; its upper level being from 25 to 30 feet deep in hard 
whitish chalk without flints, but yielding Calerites subrotundus; 
the lower level shows 24 feet of hard yellowish-white chalk with 
bands of loose nodular chalk. Inoceramus mytiloides and Rhyn¬ 
chonella Cuvieri are abundant, except near the bottom, where 
the chalk is very hard and is approaching the Melbourn Bock. 
Another good section at about the same horizon, but showing 
rather an unusual succession of beds, is exposed in a quarry opened 
in a field three-quarters of a mile east of Shirburn, the section 
seen in 1886 being : — 
feet. 
Hard nodular rocky chalk without distinct bedding, weather¬ 
ing into irregular lumps ---- --14 
Hard compact rock, breaking into large blocks 4 
Hard rocky chalk in one bed, but having a central nodular 
or concretionary band - - - - - - - 1 \ 
Compact chalk in thin beds, smooth and brittle, with marly 
partings -------- 8 
Grey marl containing lumps of hard white chalk, large and 
small, some green-coated - -- -- -- a 
Hard compact chalk in thick massive beds ; may be top of 
Melbourn Bock ------- seen for 4 
27 
The Melbourn Bock can be seen overlying the Belemnite Marl 
in the road cutting half a mile south-east of Crowell. 
