48 GASTEROPODA OF THE INFERIOR OOLITE. 
considerable depth below the worked stone. The top of this series would be the 
“solid block of bluish-grey limestone,” on which the so-called Sauzei-bed reposes. 
This Sauzei-bed is one of the most remarkable fossil-beds in Dorsetshire, and has 
mixed relations, no doubt, both with the Lower and Upper Divisions of the 
Inferior Oolite, though in drawing the line we must concede it to the Upper 
Division, This is another case of a misnomer, as far as Frogden Quarry is 
concerned, since it contains hardly any specimens of Spheroceras Sauzet. Most 
of the Ammonites are keeled, which at first sight would militate against its being 
placed in the Upper Division. Again, what I conceive to be the *‘true Sowerbyi,” 
or something very near to it, is far from being uncommon in this bed. All we can 
say, therefore, is that probably somewhere or other Spheroceras Sauzei does 
characterise a bed which is about the same horizon, and contains a somewhat 
similar facies to this one. 
The Gasteropoda in the Sauzei-bed are abundant and well preserved, and the 
matrix is on the whole favorable for extraction, being a soft, whitish limestone 
with green (? glauconitic) grains passing into the ironshot Oolite of the bed above. 
For the sake of distinction, and as indicating the position assigned to it, I call this 
bed Hj. The Gasteropoda seem to present forms that are intermediate between 
the ‘* Sowerbyi-bed”’ of Bradford Abbas and the more recognised species of the 
Humphriesianus-zone. It is very rich in Plewrotomarie@, another characteristic 
which it shares with the beds of Bayeux; in some other respects it seems to possess 
features of its own. 
At Milborne Wick the Sauzei-bed (H,) seems more or less blended with the 
main Humphriesianus-bed (H,), nor do 1 know of the distinctive development of 
this sub-stage anywhere else throughout the country. 
The main mass of the Hwmphriesianus-zone (H,) calls for few remarks. It is 
not particularly rich in Gasteropoda as far as my experience goes. Probably some 
of the specimens from H, in an ironshot matrix ought rather to be referred here. 
The remaining sub-stage of the Hwmphriesianus-zone (H;) deserves a little atten- 
tion on our part. It is a thin bed of brown ironshot Oolite, mostly of a peculiar 
character, which lies just above a bed very full of Terebratula spheroidalis. There 
is a most curious admixture of Ammonites. Am. Martinsii is common high up, 
and several species of Cosmoceras and Oppelia abound. Cosmoceras Niortensis and 
allied forms are especially numerous, and there occurs the curious little Am. 
cadomensis, which may well give its name to the bed, simply as a local name. 
Probably neither Am. Humphriesianus, nor Am. Parkinsoni properly so called occurs 
here, and it is evidently debateable ground between the two zones. It contains 
numerous species of Astarte, and many Gasteropoda. This horizon, or sub-stage, 
cannot be very far from that of P,; at Burton Bradstock. However, this must be 
lower in the geological scale, though not much. The Gasteropoda occur for the 
