96 
ORGANIC REMAINS. 
REMAINS OF FISHES AND REPTILES. 
Teeth and vertebrae of fishes ... PL II. fig. 51, 53. Speeton. 
Teeth and vertebra of saurian animals fig. 52, 54. Ditto. 
Jaw-bone and teeth of Gyrodus minor (Agassiz) fig. 55. Ditto. 
Of seventy-one species contained in the above catalogue of Speetorl 
and Knapton fossils, one (a belemnite) appears to be also found in the 
lower range of blue clay, which in Yorkshire corresponds to the Kimmer- 
idge clay ; four others (mya depressa, terebratula inconstans, trochus 
reticulatus ? ammonites Lamberti?) occur in that stratum in Wiltshire 
and Dorsetshire ; one (gryphaea sinuata) in the lower green sand range of 
Kent, twelve, or perhaps thirteen, (viz. caryophyllia conulus, spatangus 
argillaceus, plioladomya decussata, nucula ovata, rostellaria composita, 
ammonites planus ? belemnites minimus, hamites intennedius? h. rotun- 
dus, h. attenuatus, h. alternatus, h. plicatilis ? vermicularia Sowerbii,) 
belong to the blue and gray marls of Bedfordshire, Kent, and Sussex ; 
and one (terebratula subundata) is also found in the chalk. The conclu- 
sion to be drawn from this statement is, obviously, that the blue clay of 
Speeton in Yorkshire is especially to be referred to the gault or blue 
and gray marls of Cambridgeshire, Kent, and Sussex ; but that it also 
contains some characteristic indications of the Kinnneridge clay, and 
therefore we should expect that in Yorkshire these two strata are not 
separated as in the South of England. This agrees exactly with all that 
can be observed of their geological position ; for there is no evidence 
that any other stratum divides them, but on the contrary, much proba- 
bility that they are in contact. Had ostrea deltoi'dea been found at 
Speeton, there could remain no doubt on the subject ; but as that fossil is 
known to lie near the bottom of the Kimmeridge clay, its presence at 
Speeton was not to be expected, because there the lower portion of the 
clay is not exposed. Lastly, though no layers of green sand occur in 
a distinct form in Yorkshire, chloritic sand accompanies most of the 
fossils at Knapton, and many of those at Speeton. 
