exceeds 28 or 30 feet in thickness, of which from 8 to 10 feet belong to the lower subdivision. The upper subdivision immediately underlies the Fuller's Earth; and its light colour, lithological structure, and general poverty in organic remains readily distinguish it from the hard, brown, more or less massive or rubbly limestone beneath, which is everywhere very fossiliferous"[1].
Now we take it that, although the learned Dr. Holl is right as regards the position of the Dorset Cephalopoda-bed, he is not so in supposing that the lower members of the Inferior Oolite all thin out in Dorset—our view being that quite 100 feet of the sands, with its occasional bands of shelly oolite, as these occur at Bradford Abbas, really represent the lower oolitic mass of Leckhampton and Crickley, in Gloucestershire; and, in fact, our Dorset sands represent the lower freestones of Gloucestershire.
The connexion between the sands of one place (Babylon Hill) and the building-stones on the same horizon at Ham Hill is shown in the accompanying section (fig. 1).
Fig. 1.—Section from Ham Hill to Babylon Hill.
1. Cephalopoda-bed of Dorset
3. Upper Lias. 4. Lias Marls.
At Ham Hill the equivalent of the sand-bed at Babylon Hill is a reddish brown freestone, apparently made up of comminuted shells. At Babylon Hill the brown sandy beds present occasional courses of comminuted shelly oolites.
The two sections here placed in juxtaposition (fig. 2) are remarkable for their dissimilarity at first sight; but if the brown sands were a little more indurated (and the presence of a few more shells or a little more lime might well
- ↑ Quart. Journ. Geol. Soc. vol. xix.
