GREAT OOLITE LIMESTONE. 383 
rule, the Great Oolite of tliis district is everywhere distinguished 
from the Inferior by the total absence of oolitic structure. When 
dug under a considerable thickness of clay, all the beds are blue 
and of great hardness. Occasionally these beds become somewhat 
ferruginous, and are then, in their general aspect, scarcely distin- 
guishable from the Cornbrash." This is more especially the case 
in seme parts of Lincolnshire. 
The thickness of the Great Oolite Limestone is from 25 to 
30 feet near Bedford, about 25 feet at Northampton, and from 
12 to 20 feet in Lincolnshire. 
" There are many local variations in the character of its beds 
and in the general assemblage and facies of its fossils, which seem 
to indicate numerous changes in the depth and other conditions 
of the seas in which the beds were deposited. The graduation 
of the strata of the Great Oolite Limestone Series downwards 
into the Upper Estuariue Series, and upwards into the Great 
Oolite Clays is most perfect."* 
Prof. Judd comments on the general similarity between the 
organic remains of the Great Oolite Limestone and those of the 
Cornbrash. The more abundant fossils of the Great Oolite 
Limestone, some of which are locally preserved, are Nautilus 
Babcri, Cyprina lotvcana, Homomya yibbosa, Isocardia minima, 
Modiola yibbosa, M. imbricata, Ostrca Sowerbyi, O. subrugulosa, 
Pholadomya dcltoidea, P. Hcraulti, and Clypeus Mullcri. 
Remains of Cctiosaunis have been found at Ellsworth, and 
elsewhere, and other remains of Saurians and Fish-remains are 
to be found. 
LIST OF FOSSILS FROM THE GREAT OOLITE LIMESTONE. 
Cetiosaurus. 
Hybodus. 
Mosodon (Pycnodus). 
Stroijhodus magnus. 
Nautilus Baberi. 
subtruncatus. 
Natica globosa 
pyramidata. 
Nerinasa Voltzi. 
Anatina siliqua. 
Area Pratti. 
Astarte angulata. 
Cardium snbtrigonum. 
Ceromya concontrica. 
Symondsi. 
Corbicella bathonica. 
Cucullaaa concinna. 
Cypricardia bathonica. 
rostrata. 
Cyprina loweana. 
Gervillia crassicosta. 
Hinnites abjectus. 
Homomya gibbosa. 
Vczelayi. 
Isocardia minima. 
Lima cardiiformis. 
Lima duplicata. 
Lucina bellona. 
Macrodon hirsoiicnsis. 
Modiola gibbosa. 
imbricata. 
Lonsdalei. 
Myacites calceiformis. 
securiformis. 
Myacites tumidus. 
Mytilus siablasvis. 
Nucula Monkei. 
Ostrea acuminata. 
Sowerbyi. 
subruguloea. 
Pccten annulatus. 
demissus. 
* Judd, Geol. Rutland, pp. 202, 203 ; see also Aveline and Trench, Geol. part of 
Northamptonshire, p. 13 ; Morris, Geol. Mag., 1869, p. 101 ; Sharp, Quart. Journ. 
Geol. Soc., xxvi. p. 382, vol. xxix. p. 287. 
