oil 
BELEMNITES OF THE LIAS. 95 
LIAS—OOLITE. 
A complete passage by continuous change from the Upper Lias to the Inferior Oolite, 
from an argillaceous shale or clay to an Oolitic limestone, is not to be looked for; but 
there are a few localities in England where beds are interposed which mark one or more 
stages in the change of sediments, and are themselves marked as much by change of the 
forms of life as by mineral variation. My attention was attracted to this subject during 
frequent examinations of the Yorkshire coast on several occasions previous to the publica- 
tion of the first volume of my work on the strata and fossils of that coast, in 1829. 
Generally speaking, the Oolitic series terminates below in a variable sandy, irony, or 
calcareous rock, sometimes almost full of shells, at other places not yielding one. ‘Ihe 
Lias on which this rests is in general strongly contrasted with it in colour, structure, 
composition, and fossils ; but in one locality on the coast, at Blue Wick, under the Peak 
of Robin Hood’s Bay, the series of strata, including Lias below and Oolitic rocks above, 
admits of subdivisions which soften the change from Lias to Oolite, and exhibit a pretty 
full series of fossils for illustration of the life forms of the transition period. 
In my account of these beds (‘ Illust. of Geol. Yorkshire,’ vol. i, p. 91, first edition) 
they are all classed as a conchiferous (Dogger) series analogous to the Inferior Oolite of 
Bath, which at that time was universally allowed to include the sandy beds below, so well 
known and described at Bath and Yeovil. The description given of these beds at Blue 
Wick shows that they were regarded by me as “ gradually changing in the lower beds” to 
the Alum-shale. 
In 1859 the further researches of Dr. Wright (‘ Geol. Journal,’ vol. xvi, p. 1) con- 
vinced him that these passage-beds were the equivalent of the “ Cephalopodal bed” and 
sands which cap the Lias of Gloucestershire and Dorsetshire; and by the valuable 
evidence of the Ammonitidz they have been of late years pretty generally associated with 
the Lias, as the uppermost member of that formation. Of the few Belemnites which occur 
in these beds I have noticed the most conspicuous, viz. B. crregularis (Pl. XV, fig. 37), at 
Frocester Hill; B. cnornatus (Pl. XVIII, fig. 46), at Blue Wick ; B. sulci-stylus, (Pl. XIX, 
fig. 49), at Nailsworth. 
Having lately on several occasions examined many times with great care these sands 
at Bridport, where they are capped by the Oolite, and again at Yeovil under similar con- 
ditions, I am able to add to the list of species four other forms, viz.— 
Bel. Voltzii. Upper part of the Yeovil Sands, only 15 or 20 feet below the Oolite. 
Bel. tricanaliculatus, Quenstedt, ‘Cephal.,’ t. 25, figs. 13—15. Bridport Sands. 
Bel. quadricanaliculatus, Quenstedt, ‘ Jura.,’ t. xli, f. 17. 
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