106 
THE CRETACEOUS ROCKS OF BRITAIN. 
alternating with courses of hard grey chalk dipping to the 
south-east at about 7°. On the west side there are similar beds 
for about 30 feet, succeeded by some 20 feet of massive grey chalk, 
so that there seems to be a fault striking through the pit, but it is 
not clear. Many fossils have been obtained here. I found Am. 
[, Schloenb .] varians, Scaphites cequalis, Turrilites sp., Baculites sp., 
I noceramus latus d’Orb., Pecten Beaveri, and P. orbicularis; and 
in the collection of the Bev. J. Penny, of Tarrant, are Am. [ Acanth .] 
rotomagensis, Nautilus elegans, Pholadomya decussata, Inoceramus 
cuneiformis, Pleurotomaria sp., and another large naticoid Univalve : 
also a Ptychodus tooth. 
Similar beds of soft grey marl, alternating with courses of hard 
grey chalk, are exposed in the railway cutting a mile and a half 
south-east of Shillington, and here also fossils are common, the 
following being found in the lowest hard bed:— Am. [Schloenb.] 
varians, Am. [ Desmoceras ] planulatus , Scaphites cequalis, Fusus 
sp., Avicula gryphceoides, and Discoidea cylindrica. 
South-west of Shillington, and about a mile west of the rail-cutting, 
is a quarry, at the entrance to which soft marly beds are seen, but 
the chalk quarried is massive greyish white chalk. This, therefore, 
is the top of the Chalk Marl, and there is hardly room for more than 
50 feet below down to the Greensand. 
The base of the Chalk is just exposed at the top of a sand-pit 
half a mile south of Okeford Pitzpaine. This section was 
described in the first volume of this memoir (p. 164) from notes 
taken in 1891, but Mr. J. Scanes visited this pit in 1901 and 
found the upper part of the section better exposed. The following 
account has been compiled from the notes which he lias kindly 
placed at my disposal. The beds exposed are divisible as follows :— 
ft. in. 
j Chalky glauconitic marl with phosphatised nodules 
jg | and fossils.1 6 
J Bed of nodular concretions closely packed in a 
\ matrix of sandy glauconitic chalk ---20 
( Dark green glauconitic shelly sand, an irregular bed 
varying from 8 in. to 2 ft. - - average 1 4 
Nodular glauconitic sandstone - - about 2 6 
Dark green glauconitic sand - seen for 12 0 
Over 20 0 
If this account be compared with that printed in the first 
volume of this work (p. 164), it will be seen that the bed of 
nodular concretions is thicker than it seemed to be in 1891, and 
that it is separable from the Greensand below. Moreover, it 
appears to be correlative with the “-cornstone-bed ” of the 
Maiden Bradley section (see p. 148 ), which we now regard as the 
base of the Lower Chalk (or Cenomanian). Consequently, I now 
place the plane of division between Selbornian and Cenomanian 
at the base of this bed, the brackets A and B showing the 
