COENBRA.SH. 435 
vaganSfLimacardiiformis, Ostrea Sowerbyi, Rhynchonella concinna, 
Terebratula maxillata, &c. 
From a general consideration of the fauna of the Cornbrasb, 
Prof. Buckman maintained that the organic remains had more 
affinity with those of the Inferior Oolite than with those of the Great 
Oolite. It is indeed true that the Cornbrash in its sedimentary 
-characters much resembles the rngstones of the Cotteswolds, and 
the more earthy and partially oolitic limestones of Dorsetshire, 
belonging to the Inferior Oolite. The Lamellibranchs too in 
many cases comprise similar genera and species, such as Cerumya 
concentrica, Piioladomya oblita, Modiola gibbosa, M. imbricata, 
Myacites calcciformis. M. decurtalus, Ostrea flabelloides, Pecten 
demissus, P. lens, &c. Nevertheless the resemblance between 
the faunas of the Inferior Oolite and Cornbrash, according to 
Lycett, depends upon the fact that the Cornbrash fauna consists for 
the most part of a portion of those Cottes^old forms which have 
a great stratigraphical range, and pass upwards thr jugh'the Great 
Oolite.* 
The Cornbrash was a formation laid down in tranquil waters, 
Its even-beds exhibiting none of the marked false -bedding so 
conspicuous in the Forest Marble beneath. The abundance of 
fossils, the clusters of Waldheimia obovata, and W. Ingcnalis, and 
also of Avicula echinata, indicate the slowness of deposition. A 
large specimen of Ammonites macrocephalus, obtained by Prof. 
Judd from Helpstone, near Peterborough, was covered with 
masses of Ostrea and Serpula.\ We find no evidence of marginal 
-deposits, in the .4iape of conglomeratic beds, and the strata were 
probably laid down in deeper water than other members of the 
Great Oolite Series that are exposed to view. 
The rocks from various localities were examined under the 
microscope by Mr. Teall. They showed organic fragments and 
quartz grains in a matrix of granular or crystalline calcite. 
Foraminifera were noted in some rocks ; and in a specimen from 
Wincanton, where the matrix was of clear crystalline calcite, the 
material preserved in the hollows of bivalves, differed from the 
general matrix in being nearly opaque. 
LOCAL DETAILS. 
Weymoutk to Bridport. 
Commencing on the Dorsetshire coast, near Weymouth, we 
find the Cornbrash to be well exposed on the northern side of 
Eadipole Lake, where the following succession of beds may be 
traced : 
* Cotteswold Hills, p. 110. 
t Geol. liutland, p. 225. 
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