LOWER CHALK—OXFORD AND BUCKS. 
177 
ft. 
Soil and soft flaky marl -- - - - - 4 
Irregular lumps of hard greyish chalk in two bands, separated 
by soft marl ---- ____4 
Blocky marl or “clunch” in irregular beds - - - - 12 
Many of the characteristic fossils of the zone may be obtained from the 
hard lumps in this quarry (see p. 183). 
A boring was made at Bulbourne, north of Tring, for the Birming¬ 
ham Canal Company in 1855, and specimens are preserved at the 
local office of the Company at Marston. From an examination 
of these specimens made by me in 1884 the beds traversed by the 
boring seem to have been as follows : — 
ft. 
Lower 
Chalk, 
140 
feet. 
* 
Gault, 
258 
feet. 
L.G.S. 
Soft Chalk --------- 
Hard grey sandy chalk (Totter nlioe Stone), 
samples from 25j and 274 feet - 
Soft chalk marl -------- 
j Soft bluish marls ------- 
Soft grey marl with harder lumps - 
Grey micaceous silty marl ------ 
Hard rocky chalk, with impression of Am. 
\Schloenbaehia\ varians at 714 feet 
Soft grey and blue argillaceous marls - 
/ Dark micaceous grey and greenish sandy marls 
(? Selbornian) ------- 
Light grey clays ------- 
i Clay with phosphate nodules ... - - - 
Gault clays - - - 
\Clay full of sand and pebbles « 
fBrown sands 
\ Greenish sand - - - 
20 
9 
5 
25 
]0 
? 4 
? 05 
10 
80 
1 
159 
8 
62 
5 
465 
Both the Gault and the beds below the Totternhoe Stone are 
thicker than usual, but if the record is reliable, the Chalk Marl 
has here a thickness of 111 feet. The hard rocky bed at 714 feet 
is probably one of those seen in the quarry on West End Hill, for 
the sample much resembles them. 
Zone of Holaster subglobosus. 
* 
The Totternhoe Stone ^ with some of the underlying Chalk Marl 
and the greater part of the overlying zone, was formerly well exposed 
in the quarries (now overgrown) by the side of the main road on 
Crowmarsh Hill. As seen in 1885, the Totternhoe Stone was 
about 4 feet thick, forming a band of massive brownish-grey chalk 
which could be quarried in large blocks. At the present time the 
upper end of the quarry shows about 30 feet of nearly 
white blocky chalk, the bedding of which is obscured by the curvi¬ 
linear jointing of the mass. Between the foot of this and the level 
on which the kiln stood there must be 35 or 40 feet of similar chalk, 
whitish above, but becoming grey below, and containing Aw, 
[Acanth.] rotomagensis , 
