170 THE CRETACEOUS ROCKS OF BRITAIN. 
fu in, 
S§ Greyish bedded chalk, rather hard - - - - 10 0 
o Soft grey chalk - - - - - - - - 3 0 
'3^ Hard rocky grey chalk ------ 1 0 
aj Grey chalk with shaly partings, passing down into 
§ I hard grey bedded chalk - - - - - 5 0 
Totternhoe Stone. — Brownish-grey stone, firm and 
rough to the touch, with many phosphatic nodules 
and fossils - -- -- -- -20 
Grey chalk marl, breaking conchoidally - - - 5 0 
Very hard compact limestone (siliceous) - - - 1 9 
2 Shaly grey chalk - - - - - - 0 6 
U-J 
0 
S 
* 
Hard rough grey chalk (siliceous 
and containing 
03 
Q 
fossils) ----- 
- 
- 
O 
9 
h~l 
O 
ci 
Loose grey marly chalk - 
- 
- 
3 
0 
si 
Hard rough grey chalk (siliceous) 
- 
0 
8 
Loose grey marly chalk - 
- 
- 
2 
0 
Firm blocky chalk, seen for - 
- 
- 
3 
O 
37 8 
Am. [Schloen.] varictns is common in all the beds below the marl 
which underlies the Totternhoe Stone, but does not occur in that 
marl nor in the stone above, except in the condition of a phosphatic 
cast. 
All the hard courses in the Chilton section contain sponge-spicules, 
but these are most abundant in the highest and hardest of the beds. 
Some of the spicules are still siliceous, but others are replaced by 
calcite. All these beds also contain minute globules and 
aggregations of colloid silica, and the amount of this is also 
greater where the proportion of sponge-spicules is greater. 
The cutting on the Great Western Railway by Moulsford Station 
exposes a good section of beds which must be about 60 feet below 
the Totternhoe Stone. These are : — 
ft. 
Marly chalk in courses separated by layers of soft shaly 
marl - -- --. 10 
Soft grey marl with lumps of harder chalk - 8 
Hard rocky chalk weathering with lenticular lumps; 
fossils abundant - -- -- -- - 2 
The fossils found here include Am. [Schloenb.] varians, Am. 
[. Acanth .] Mantelli, Inoceramus latus, and Rhynchonella Schloen- 
bachi ? 
Zone of Holaster subglobosus. 
Below White Horse Hill, on the promontory known as Dragon 
Hill, there is a quarry open in chalk which must by its level belong 
to the zone of Holaster subglobosus, but which has an unusual cha¬ 
racter. The beds seen in 1887 were : — 
ft. 
Broken chalk, with thin bands of greyish marl - - - 5 
Hard rough greyish chalk, containing Am. [llapl .] Austeni , 
and Am. [Acanthi] rotomagensis, weathering into irregular 
lumps .- 6 
Whiter blockv chalk with a more even fracture - ° - 8 
