Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/615

Rh nifer just named, which, however, is not confined to it, but is met with in all the beds, although never in the exceeding numbers which characterize the red or Heterostegina-stratum.

Of Vertebrata, out of 15 forms in the Sand bed, only two species of Pycnodont fishes have, so far as I know, turned up in the Upper Limestone.

There is, however, a decided agreement between the Invertebrata, as is shown by no less than 14 genera and many species being common to both.

The genus Pecten, so plentiful in the Maltese Miocene, is represented in the Sand bed by four species, also met with in the Upper Limestone. Of the Brachiopoda, Terebratula sinuosa and Megerlia truncata are common to both formations, besides nine species of Echinodermata, whilst nearly all the Polyzoa, Cœlcnterata, and Protozoa seem undistinguishable.

III. The varies very much in thickness, thinning out for a depth of upwards of a hundred feet to scarcely an indication of its presence. It is the most perishable of the beds, and is being rapidly denuded. It varies in colour and composition, from a dark blue or drab colour to a light brown or grey; some sorts form a fair plastic clay, being both stiff and tenacious, whilst the light-coloured run in the form of horizontal bands.

Of foreign components, nodules of sulphuret and peroxide of iron, and gypsum, are plentiful, and often incrustthe fossil remains, whilst the crystalline and lamellar varieties of gypsum are also common. Besides these, nodules of an ochreous-coloured clay perforated by Pholad-borings, and containing casts of these mollusks, are not rare, and are apparently derivative.

The most characteristic fossils of the Marl are a cuttle-bone of a small Sepia and casts of Nautilus, which Dr. Woodward, F.R.S., and his late brother, Dr. S. P. Woodward, F.G.S., assured me are undistinguishable from the typical specimen of Nautilus ziczac.

The organic remains are not, as a rule, in a good state of preservation; however, out of 25 genera and species of Mollusca belonging to the Sand bed, I have recognized as many as 13 in the Marl. The only Brachiopod of the two upper formations that I have likewise found in the Marl is Terebratula sinuosa, which is not uncommon, and is the only representative of the group I have seen from this bed.

Of the 11 Echinodermata of the Sand bed not a single species has turned up hitherto to my knowledge in the Marl; but Echinolampas Laurillardi is common to the Marl and the Upper Limestone, whilst Hemiaster Scillæ makes its first appearance in the Marl. These are the only Echinida I have found in the latter, excepting ossicles of un- determined species of Asteroidca, which are found in all the formations.

The point of transition between the Marl and the Calcareous Sandstone is often abrupt.

The latter presents considerable variability both in the general