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THE CRETACEOUS ROCKS OF BRITAIN. 
In the lane leading out of the road from Homington to Combe 
the top of the Lower Chalk (with the Belemnite marl) and the 
overlying Melbourn Rock are well seen. At Combe Bisset there is a 
large pit in the lower part of the Middle Chalk about 40 feet deep ; 
the chalk at the bottom is hard and contains Inoceramus mytiloides; 
higher up it is tough and massive with several layers of soft marl, 
and near the top there are many grey flints. The beds are dipping 
to the north at about 4 deg. 
There are no good quarry sections in this division along the south 
side of the Yale of War dour, but the whole of the Middle Chalk 
can be traced in the roadway ascending Compton Down ; first, 
the rough nodular chalk of the Rhynclionella Cuvieri zone, then 
the firm white chalk of the Terebratulina zone overlain by the hard 
rocky beds of the Chalk Rock. 
Along the northern border of the Yale of Wardour there are a 
few places where the zone of Rhyne. Cuvieri can be seen in spite of 
the high dips. 
A quarry north-east of Baverstock shows about 25 feet of this 
zone, hard, rough and nodular in the lower part, which cannot be 
far from the Melbourn Rock. The two common fossils were found 
in the upper beds, and the dip is about 33 deg. to the north-east. 
The Melbourn Rock, passing up into hardish bedded chalk con¬ 
taining Rhynclionella Cuvieri and Inoceramus mytiloides, is also 
exposed in a small pit three-quarters of a mile north-east of 
Dinton. The dip here is about 20 deg. north, and an old excavation 
close by, which must have shown the Terebratulina zone at the 
Chalk Rock, is still exposed at the northern end, dipping at 45 deg. 
A quarry half a mile north of the village of Ridge shows the 
following section, the beds dipping at about 15 deg. to the north 
feet. 
Hard bedded whitish chalk -.15 
Hard yellowish nodular chalk in regular beds, with several 
layers of marl 10 
Marked layer of marly chalk 
Hard nodular yellowish chalk (Melbourn Rock) 5 
Greenish grey marl and marly chalk 6 
Talus concealing lower beds. 
The Melbourn Rock is exposed behind the lime-kiln of the quarry 
on the road from East Ilnoyle to Hindon, and in the quarry itself 
there is at the base 2 feet of hard cream-coloured chalk, overlain 
by a seam of greenish marl; and then about 50 feet of firm white 
chalk in thick beds, succeeded by Chalk Rock and Upper Chalk, 
The total thickness of Middle Chalk here can hardly be more than 
80 feet. 
The whole of the Middle Chalk, with a total thickness of only 
70 J feet, was traversed in a boring at Lower Pertwood, a farm 
If mile east.of Monkton Deverill; the boring was made by Mr. 
H. J. G. Hole, of Poyntington, Sherborne, to whom I am 
