GREAT OOLITE : WILTSHIRE. 
255 
that here, as elsewhere, the great oolite merely assumes the 
characters of the forest marble."* 
Subsequent writers have, as a rule, simply repeated these 
opinions, and it is only necessary to mention that in 1876, I 
ventured to say that " In the district south of Frome the Great 
Oolite thins away entirely, and is represented partly by the 
Forest Marble, and perhaps also by the Fuller's Earth." f 
It might have been expected that the officers of the Geological 
Survey would long ago have settled the matter ; but while the 
Oolitic area in question was surveyed geologically by John 
Phillips and H. W. Bristow, and the map shows the superficial 
distribution of the strata, yet the memoirs furnish but little help 
towards a solution of the problem. This, however, is not 
surprising when we come to examine the debatable ground. 
For, unfortunately, where the dying away of the Great Oolite 
takes place, there is a singular absence of sections ; an absence 
no doubt due to the fact that there is little or no building-stone 
to be had, and that the clays would be too marly for brick- 
making. Moreover, Lonsdale's paper is such a model of careful 
and accurate work, that we may be sure he would have recorded 
any sections, open in his time, that threw a light upon the 
subject. 
FIG. 80. 
Diagram-section to show the attenuation of the Great Oolite, near 
Bradford-on-Avon. (Distance about 6 miles.) 
North. South. 
Box 
Brook. 
Kings Down. 
Bradford-on- 
Avon. 
Wingfield. 
10. Oxford Clay. 
. 9. Kellaways Beds. 
8. Cornbrash. 
7. Forest Marble. 
6. Bradford Clay. 
5. Great Oolite. 
4. Fuller's Earth Clay, with Fuller's Earth 
Rock. 
3. Inferior Oolite. 
2. Midford Sands. 
1. Lias. 
The problem, however, may be attacked from a more general 
point of view, and the questions that arise are these. Does the 
Great Oolite pass laterally into the Forest Marble, or into the 
Fullouian Beds (Fuller's Earth), or into both ? Does it wedge 
out independently of either formation, there having been a pause 
in deposition further south ? Or, was it deposited over much of 
the south of England and afterwards denuded in Oolitic times ? 
We may consider first, the relations of the Great Oolite and 
Forest Marble. 
* Trans. Geol. Soc., ser. 2, vol. iii.p. 254. 
f Geol. Eng. and Wales, ed. 1, p. 188. 
