PROF. J. BUCKMAN ON THE MIDFORD SANDS. 739 
It should, however, be noted that in the sands there are occasional 
Seams of carbonate of lime, apparently derived from the decay of 
layers of Testacea which have been decomposed in the porous stratum. 
The Gloucestershire sections and the Somerset and Dorset ones 
agree in having a Cephalopoda-bed at the base and another high up. 
Our grand Cephalopoda-bed in Dorset is the equivalent of the Gry- 
phite-Grit on the top of Leckhampton Hill, and both are marked by 
a list of characteristic Ammonites, amongst which are the following :— 
Inst of Ammonites common to the Upper Cephalopoda-beds 
of Dorset, Somerset, and Gloucester. 
Ammonites Brocchii, Sow. Ammonites Humphriesianus, Sow. 
Sowerbii (Brownii?), Sow. Parkinsoni, Sow. 
concavus, Sow. subradiatus, Sow. 
corrugatus, Sow. —— leviusculus, Sow. 
Now these species are common to both districts ; and be it recol- 
lected that as sand underlies this wpper Cephalopoda-bed in Dorset, 
while sand underlies the lower Cephalopoda-bed in Gloucestershire, 
these two beds have been considered as belonging to the same 
horizon ; it was so thought by the late Prof. Phillips, and hence he 
aimed at getting rid of the difficulty by naming these as follows:— 
** MiprorD SANDS. 
«The last of the liassic strata, to which the inferior oolite has not 
quite relinquished its ancient claim, is a variable series of fine sands, 
deposited on the upper lias clay in such a manner as often to defy 
the geologist to draw a hard line between them. ‘These sands are 
bluish under ground, yellowish at the surface. They are covered in 
many districts in the south of England by calcareous and shelly beds, 
which on the first view appear naturally associated with the oolitic 
rocks above; but they contain many fossils which are frequent in the 
sands and not common in the oolites. Thus we have in general 
terms 
Inferior oolite above. 
Shelly calcareous bed. 
Fine-grained sands. 
Upper lias clay below. 
“ Here, then, is a transition series of beds, which for convenience 
and for reasoning may be joined with either or both of the greater 
deposits, which, in fact, they feebly tie together” *. 
Now when we consider that the sands at Midford are the equi- 
valents of a great mass of the Inferior Oolite of Leckhampton, Hors- 
field, and Crickley, it will be seen that, however the name of either 
Oolite or Lias sands for the beds below the Gloucestershire freestones 
may apply, the term Midford Sands cannot apply to the equivalents 
of the freestone and ragstone beds of the Cotteswolds, of which these 
so-called Midford Sands undoubtedly are the equivalents. 
Hitherto we have described the beds below the so-called Cephalo- 
* Geology of Oxford and the Valley of the Thames, p. 118. 
