GREAT OOLITE : WILTSHIRE. 257 
Although the persistence of this fossil-bed had not before been 
dwelt upon, yet Davidson recorded several species from the " Brad- 
ford Clay of Radipole near Weymouth, and from Burton Brad- 
stock ; these fossils were collected by Mr. J. F. Walker and Mr. 
Darell Stephens, to whom we thus owe our first acquaintance 
with the extent of this horizon.* 
I have seen no evidence in this southern region of the Crinoid 
growth in situ, as we have it at Bradford-on-Avon, but the 
occurrence of this fossil-bed on top of the comparatively barren 
Fuller's Earth is significant, for it marks a considerable change in 
conditions. The Kev. O. Fisher, however, informed me (1889) 
that years ago he found evidence of Crinoid growth in situ north 
of Langton Herring. 
The evidence before us is that the Bradford Clay is present in 
Wiltshire and in Dorsetshire, in the one area resting directly on 
the Great Oolite, and in the other on the Fullonian (Fuller's 
Earth) ; and the natural conclusion is that the Great Oolite of 
Bath and Bradford-on-Avon does not pass into the Forest Marble 
of Dorsetshire. 
We have now to consider the relations between the Great 
Oolite and the Fullonian Beds. Junction-sections are unfortu- 
nately in most cases the exception rather than the rule ; but in 
the area north of Bath, and extending to Stonesfield in Oxford- 
shire, there is abundant evidence to show the intimate connexion 
between the Fuller's Earth and the Great Oolite. This consists 
in the alternation of clays and stone-beds. I have noticed it on 
the slopes of Lansdown, N.W. of Charlcombe. In the Stroud 
area attention has been directed to the passage by E. Witchell, 
who observed that " the upper part of the [Fuller's Earth] for- 
mation consists of a sandy clay alternating with beds of sand- 
stone, brown on the surface, blue internally, and closely resembling 
the Stonesfield slate, except that it is less laminated. The 
passage from the Fuller's Earth to the Stonesfield slate is shown 
in the disappearance of the clay and the greater development of 
the sandstone beds which assume a more persistent character."! 
Similar indications of a transition have been shown on Seven- 
ham pton Common, and in the cuttings of the railway betwee, 
Cheltenham and Hook Norton near Banbnry ; and they are 
observable at Stonesfield in the one open working I was able to 
examine, where there is an alternation of marls and stone-beds 
above the " slate." Moreover this feature at Stonesfield is con- 
firmed by the careful record of the strata made in 1827 by 
Fitton,J when he sought to demonstrate the stratigraphical position 
of the first Mammals found at Stonesfield, although he did not at 
that time convince all the scientific sceptics. (See p. 312). 
* Supp. to Brit. Jurassic Brachiopoda, pp. 151, 156, 173, &e. 
t Geol. Stroud, pp. 70, 71. 
J Zool. Journal, rol. iii. p. 402. 
75928. 
