108 
ORGANIC REMAINS. 
mya literata, and turritella muricata, are repeated in the cornbrash and 
oolites below it; others, as spatangus ovalis, terebratula socialis, and 
ammonites perarmatus, are found as low as the Kelloways rock; and 
sanguinolaria undulata and astarte carinata? have been met with in 
the Oxford clay ; but a considerable number remain, which are so 
constantly associated with this rock, that they may be employed to 
identify it in a case otherwise doubtful. Such are isocardia tumida, 
modiola bipartita, pinna lanceolata, pecten vagans, lima rudis, gryphtea 
bullata, and ammonites vertebralis ; not to mention several rarer species, 
of which the value in characterizing the rock remains to be ascer- 
tained. 
Mr. Murchison’s paper, to which I have already referred, on the 
geology of Brora, affords an opportunity of applying these results to 
determine the geological relation of the rubbly limestone and sand- 
stone of Braambury hill, the uppermost stratum of that district. In its 
position with respect to other conchiferous beds there, it agrees with the 
calcareous grit of Yorkshire, and amongst the fossils which Mr. Mur- 
chison has there collected, we find gryphaea bullata, ? modiola bipartita, 
pecten vagans, and ammonites vertebralis. Of these I have had the 
opportunity of consulting specimens, which the liberality of their dis- 
coverer has placed in the museum of the Yorkshire Philosophical 
Society, and others presented to me by my friend Mr. Marshall. The same 
museum contains a suite of fossils from the calcareous grit of Oxford- 
shire, presented by Dr. Buckland, amongst which we recognize ammo- 
nites vertebralis and pinna lanceolata. Ammonites vertebralis was 
obtained by Mr. Smith from this rock at Derry-hill, Wilts, and pinna 
lanceolata by Professor Sedgewick at Weymouth. In these instances 
the zoological characters of a rock are shewn to be constant from one 
end of the island to the other, though its thickness and mineralogical 
appearance are subject to great variations, and in one example the 
deposit is insulated and distant four hundred miles from its kindred 
strata. The coralline oolite, (and calcareous grit?) with pecten viminalis, 
ammonites plicatilis, &c. contribute to form the upper part of the Jura 
limestone of Switzerland, and have been observed at several places 
on the north coast of France, 
