From the Old Red Sandstone of Caithness, four species of Dipterus were originally named by Sedgwick and Murchison, those being as follows:—

1. Dipterus brachypygopterus, anal fin short.

2. D. macropygopterus, anal fin long.

3. D. Valenciennesii, small in size, narrow in shape.

4. D. macrolepidotus, not characterized although figured.

It is evident from the figures of “D. macrolepidotus” that it does not belong to the same genus, even to the same family, as the other forms. Those have circular scales, whereas in “macrolepidotus,” the scales are rhombic, and the head bones are clearly seen to be very different from those of Dipterus.

The largest mammals of the American Miocene were the huge Brontotheridæ, which lived in great numbers on the eastern flanks of the Rocky Mountains, and were entombed in the fresh-water lakes of that region. They were larger than the Dinocerata of the Eocene, and nearly equalled in size the existing Elephant. They constitute a distinct family of Perissodactyles, and were more nearly allied to the Rhinoceros than to any other living forms.

Coming along the cliffs from Boscastle towards Tintagel, at the part just seawards of the village of Trevalga, and between the outlying rocks known as “Short Island” and “Long Island,” we see one or two limited outcrops of a schistose rock different from the surrounding slates, shales, etc. A thoroughly good sight of it is not, however, obtained till we reach the extreme north side of Bossiney Cove, a little way south of Long Island, when a very fine exposure of the sheet in question is observed, lying in among the sedimentary rocks, sharply marked off from them at contact, so that the junction-lines can be seen distinctly even from some distance.

Last summer I had the pleasure of passing a fortnight in the Channel Islands under the guidance of my friend the Rev. E. Hill, who has done so much to elucidate their geology. During our short visit to Sark we spent some hours in the beautiful little cove called Port du Moulin, examining the interesting sections of the hornblende-schist and underlying gneissic rocks. I was wandering on the beach looking at the wave-worn boulders which afford most interesting studies of the structure of this crystalline series, when my eye was attracted by one which differed much from the rest, and resembled a dark-coloured serpentine of a slightly exceptional character. With some difficulty, owing to its form, I detached a tolerable specimen, and on examining the fresher surface, felt convinced that I had found a rock composed chiefly of an altered olivine and a silvery talc-like mineral.

Abundant as the remains of the Mammoth and its associated group of Pleistocene Mammalia are in the adjacent valleys of the Medway and the Cray, none have been yet recorded in the valley of the Darent, to which the Mammoth no doubt commonly resorted at the same time. One reason may be that this valley is very bare of Drift, and between Dartford and Otford there is not a single pit in the little drift-gravel that is met with.

The rocks forming Housel Bay consist of the normal dark hornblende-schists with the exception of those out of which the charming little Cove bearing the same name has been formed, which holds nearly the central part of the Bay, facing the south-east.

Subterranean landslips differ from landslips occurring in cliffs along the coast, and in escarpments elsewhere, in that, a fissure having been formed and its sides become separated (Figs. 2 and 3 a), so that they are without support along the line of division, it may happen that by the giving way of some soft or unconsolidated stratum (b), at any depth, from a few feet only, down to the molten nucleus, wedge-shaped masses (c) extending parallel to the fissure would break off (d) and slipping down strike against the opposite wall (Fig. 3e) and thus fill up the fissure.

In going through the remains of Chelonia preserved in the British Museum I came across two vertebræ from the Wealden of the Isle of Wight, which had been inadvertently included in that series. These specimens (B.M. No. R. 901) formed part of the collection of the late Rev. Mr. Fox, and clearly indicate a small Dinosaur allied to the genus Cœlurus.

An interesting paper has lately been contributed to this Magazine (December, 1888, p. 532), by Dr. Gustav Lindström, of Stockholm, in which he announced his discovery of the earlier, or Nautilus stage, as he termed it, in several specimens of Ascoceras from the Silurian of the Island of Gothland. I find, however, in looking over the supplementary volume of the Syst. Sil. du centre de la Bohême,3 that Dr. Lindström's discovery has been anticipated by M. Barrande, who observed and described two of the normal chambers (Nautilus stage, of Lindström) attached to a specimen of Ascoceras Murchisoni from the Silurian strata (Étage E) of Karlstein in Bohemia.