268 
LOWER OOLITIC ROCKS OF ENGLAND : 
Here the upper beds, which include the Scallett, are probably 
on the horizon of the Kemble Beds. 
In the railway-cutting west of Corsham railway-station, we 
find immediately beneath the grey and yellow marl that belongs 
to the Bradford Clay, a group of false-bedded buff oolites with 
Pecten and Trigonia. The eastern entrance of the Box tunnel 
is situated in these upper beds of Great Oolite, and the tunnel 
penetrates, this formation, as well as the Fuller's Earth and 
Inferior Oolite, in its extension westwards. 
The Great Oolite has been extensively mined on the southern 
side cf the railway, south-west of Corsham. From 10 to 25 feet 
of freestone in several beds has been worked at various depths up 
to about 100 feet from the surface. The "Corsham stone" is 
said to underlie the Bath or Box " Ground stone," and judging 
by the maximum thickness of the freestone -beds here obtained, 
we may infer that beds lower than those mined at Box are 
obtained near Corsham. The mines are reached by inclined 
tunnels which are driven through the superincumbent Forest 
Marble. 
Prof. Hull notes that freestone was worked by means of a 
shaft 70 feet deep at Lower Pickwick.* A boring made in 1880 
by Messrs. Le Grand and Sutcliff at Corsham (for Messrs. Randell, 
Saunders and Company), reached the Great Oolite at a depth of 
about 68 feet. (See p. 356.) 
To the W.S.W. of Yatton Keynell there is an old quarry where 
the Great Oolite has been extensively worked. The following 
section was noted in 1886 in company with the Rev. H. H. 
Winwood : 
Forest Marble. J Flaggy oolitic limestone 
(Bradford Clay.) \ Clay - 
f Shelly oolite 
j Marly layer - 4 to 
Upper I Marly and shelly oolites 
Division. "\ Marl - 
J Irregular band of shelly oolite 
(^Shelly layer, with Terebratula 
f Fine false-bedded oolitic freestone 
Lower J Irregular rubbly and ferruginous 
Division. j bed, with Echini and Sponges - 
I False-bedded oolite ... 
FT. IN. 
4 
10 
I picked up one specimen of Terebratula coarctata which 
probably came from the clay at base of the flaggy limestone at 
the top of the quarry. The section was described by Prof. Hull 
as exhibiting the junction of the Upper and Lower " Zones " of 
the Great Oolite.t The upper beds of the Great Oolite here 
contain many of the characteristic Bradfordian fossils, and show 
the intimate connection between the Great Oolite and Forest 
Marble. 
* Geol. parts of Wilts and Gloucestershire, p. 13. 
t Geol. parts of Wilts and Gloucestershire, pp. 13, 14. 
