LoWEil CUaLK— NOUTH HORNET* 
109 
In the roadway east of Sutton Waldron the base of the Melbourn 
Rock is seen to rest on a soft buff-coloured marl, with hard greyish 
chalk below, and a few feet lower there is blocky white chalk. There 
is a small quarry in similar blocky chalk by the side of a parallel 
road 250 yards north of this. 
The next place where this part of the chalk is visible is a quarry 
about half a mile south-east of Okeford Fitzpaine, west of the Stour. 
Here the Melbourn Rock is well exposed, and its massive basement 
bed passes down into whitish chalk, which breaks along the bedding 
planes and does not contain nodules; of this there are about 9 inches. 
Below it is a thin layer of grey marl, resting on blocky greyish 
white chalk, without definite bedding, of which about 8 feet are 
exposed. Here, therefore, there seems to be a local absence of the 
Belemnite Marls. 
The quarry at Belchalwell has already been mentioned ; the 
Melbourn Rock is seen at the top of this, only a thin seam of marl 
dividing it from the blocky whitish chalk below. 
2. West Dorset. 
Under this heading will be described the Lower Chalk along the 
main escarpment from Melcombe Bingham, westward by Buckland 
Newton, Evershot, and Cheddington, as well as in the country 
around Cerne, Maiden Newton, and Beaminster. In this district 
the formation becomes still thinner, varying from 100 to about 
60 feet. 
As already stated (p. 108), the Chloritic Marl proper has thinned 
out in North Dorset before reaching Bingham, and there is no longer 
a passage from Selbornian to Chalk. On the contrary, there is in 
most places a clearly-marked plane of division between the two 
formations ; the uppermost bed of the Greensand is a hard greenish 
glauconitic sandstone, the surface of which is uneven, waterworn, 
and cracked; the lumps and sides of the cracks are coated with green 
matter, and frequently bear small attached Serpulse and young 
Oysters. It has evidently been a water-washed surface during a 
period of non-deposition. On this surface rests a soft glauconitic 
chalk, the base of which is often a regular nodule-bed full of light 
brown phosphatic nodules and pliosphatised fossils. 
This is the bed referred to by Professor Forbes and Mr. Bristow 
as containing so many specimens of Scaphites cequalis and Galerites 
castanea, and also as being evidently the base of the Chalk. 
Grains of quartz and glauconite are abundant in this basement bed, 
but rapidly diminish in number above it, the material passing into 
a pure whitish chalk. The fauna of this nodule-bed is the fauna 
of the Chalk Marl, and not the special fauna which is found in the 
Stauronema zone of Wiltshire and the Isle of Wight. A large number 
of species are, of course, common to both ; but in the Dorset 
nodule-bed certain fossils, such as Stauronema Carteri itself, are 
absent, and others are common which are very rare or absent in 
