FOREST MARBLE: WEYMOUTH. 341 
the preservation in current-bedded deposits of shells composed 
mainly of calcite. 
The formation generally bears evidence of its deposition in 
shallow waters, under marine conditions ;* indications of estuarine 
characters, if we may judge by the presence of variegated clays, 
are more distinctly met with when we pass beyond the limits of 
the Forest Marble, and reach its approximately equivalent strata 
of Great Oolite Clay. 
LOCAL DETAILS. 
Weymouth to Bridport. 
We first meet with the Forest Marble along the centre of 
the Weymouth anticline* in a somewhat faulted tract extending 
from Kadi pole to Langton Herring. The oldest strata exposed 
here belong to the Fullonian 'Fuller's Earth), which is shown on 
the banks of the Fleet south of the last-named village. The 
upper part of that formation consists of about 6 feet of clay, with 
bands of pale earthy and flaggy limestone ; and this is overlaid 
by a very fossiliferous band of earthy marl about 2 feet thick, 
which constitutes the base of the Forest Marble series, and repre- 
sents the horizon of the Bradford Clay of Wiltshire. This 
fossiliferous band contains in such abundance Rhynchonella Boueti 
and R. varians, that it may be spoken of as a Rhynchonella-bed. 
It is best exposed on the margin of the Fleet at a spot known as 
Herbyleigh (or Herbury), where it is overlaid by clays and shaly 
limestones ; and it may also be seen on the borders of the West 
Fleet, south-west of Langton Herring. I examined this portion 
of the coast in 1884, when I was accompanied by Mr. Henry 
Keeping, who had previously visited this very rich collecting 
ground, although its importance had not been generally recognized. 
Some species of Brachiopoda had however been formerly col- 
lected from the neighbourhood by Mr. J. F. Walker and Mr. 
Darell Stephens, and from Radipole by R. Damon ; and the 
species were regarded as suggestive of the presence of the Bradford 
CJay.f Later on in the same year, I traced this RkynchoneUa- 
bed, westwards near Burton Bradstock and Eype, and the fossils 
collected are tabulated in the list given on p. 344. 
We have no clear section, in this moat southern region, of the 
entire series of beds composing the Forest Marble, but the 
sequence at Radipole and Langton Herring appears to be the 
same as that exhibited in the cliffs near Bridport Harbour. We 
find an upper division (beneath the Cornbrash) of blue, brown, 
and greenish-grey clay with thin leaves of limestone and occasional 
bands or lenticular beds of shelly limestone and nodules of " race " 
(shown in places to a depth of 8 feet, but doubtless much thicker). 
Then there is a central division, of hard shelly limestone and 
false-bedded flaggy and sandy oolite, with occasional ochreous 
galls and lignite ; beds which are quarried for local building- 
f See also De le Beche, Mem. Geol. Survey, vol. i. p. 285. 
j T. Davidson, Supp. to Jurassic Brachiopoda (Pal. Soc.), p. 156 ; Damon, GeoL 
Weymouth, 1884, p. 15 ; and H. B. W., Proc. Geol. Assoc.. vol. ix. p. 207. 
