Mr. alfred craven, who for some months past has been occupied in making a collection of the organic remains found in the Gault at Folkestone, has submitted to me for examination and description (if requisite) a specimen of a Pycnodont jaw which, both for the perfect condition in which it is preserved and for the peculiarity of its characters, is worthy both of description and representation. The specimen is the right mandible with most of the tritoral teeth preserved in their natural position. It betokens a fish of the largest size of the family to which it belongs, rivalling in this respect even the Pycnodus gigas of the Jura beds. The symphyseal border (PI. III. Fig. 1 s) measures two inches and eight-tenths of an inch in length, and half an inch in thickness. As the anterior extremity is wanting, the natural size was probably half an inch longer. The outer margin of the jaw measures four inches, and the basal line—connecting the outer and symphyseal elements of the triangle—three inches and two-tenths. The dental armature is composed of four ranks on the anterior and three on the posterior area of the mandible. The inner row (Pl III. Fig. 1 a) consists of teeth very considerably larger than those of the succeeding rows. Six of these are retained; but as the anterior extremity of the bone is broken, there were probably one or two more. The individual teeth measure nine-tenths of an inch by four-tenths. They are elliptic in outline, but slightly crescentic on the anterior margin.

“The earliest known example of a fossil Macrourous Decapod Crustacean was obtained by Prof. Prestwich from the Pennystone Ironstone of the Coal-measures, Coalbrook-dale, Shropshire, and was at that time referred by Prof. H. Milne-Edwards, who examined it, to the Phyllopoda under the name of Apus dubius (see Trans. Geol. Soc. Lond., 1836, 2nd series, vol. v. p. 413). In 1844 some further remains of this genus were noticed by W. Ick, Esq., F.G.S. (see Quart. Journ. Geol. Soc. Lond., vol. i. p. 199).

The specimen referred to in the following note is I believe the first example of a Macrourous Crustacean from the Carboniferous of Nova Scotia; and it is interesting to find, as pointed out to me by Mr. Woodward, that its affinities are so close with the long known Palœocarabus dubius of Prestwich, and Anthra-palœmon of Salter, from the English and Scottish Coal-measures. It was found by Mr. Albert G. Hill, manager of the Cumberland Coal-mine, at the South Joggins in Nova Scotia, in one of the bands of black bituminous limestone which occur in the middle part of the Coal Formation.

During a recent excursion into Teesdale I paid a visit to certain Mica trap-dykes discovered by my friend Mr. W. Gunn, and to a section of the Carboniferous beds below the Whin Sill of Falcon Clints, near Caldron Snout, which suggested the question whether there is not a base to the Carboniferous beds in that part of Teesdale.

The rock Lherzolite has been described by Prof. Zirkel in his valuable Beiträge zur Geologischen Kentniss der Pyrenäen (Zeitschrift der Deutsch. Geol. Gesel., vol. xix. p. 68), but is generally passed over with the briefest mention or entirely omitted in English works on Geology. Even in Cotta's “Rocks Classified and Described” it is barely noticed, and the word is left out in the index. On this account, and seeing that, so far as I am aware, no description of its microscopic structure has yet been published, a notice, embodying the results of Prof. Zirkel's paper, and of a brief visit of my own to this not very accessible locality, may be useful to students.

In all our text-books of Geology, the action of floating Ice is referred to as an agent of great power in producing physical changes. Its two chief forms are those of Coast Ice and Icebergs. Much has been written about the latter of these, but about the former very little. In the Geological Magazine, July, 1876, in an article on Ice and Ice-work in Newfoundland, I endeavoured to show that the greater agent of the two was Coast Ice, a view which has been subsequently strengthened by observations on the Coast of Finland. In this paper I had occasion to refer to the laxity with which the conditions under which Icebergs float have been spoken about. Thus, in Jukes and Geikie's Text-Book of Geology, p. 416, we are told that because “about eight times more ice of an iceberg is below water than above,” therefore “a mass which rises 300 feet above the waves has its bottom 2400 below them.”

I have to thank you for your kind letter of the 24th of December, 1875; it affords me great satisfaction to hear that my remarks about the New Hebrides have interested you.

In the summer of 1872 I visited Norway, and wrote the following brief notice of certain high-level terraces immediately on my return to England, but kept it back that I might first consult some papers on Norwegian terraces that had appeared in the closing numbers of “Scientific Opinion”; these I was not able to meet with for so long a time that I gave up the idea of sending my notice to the press. I am now induced to do so, because I see that the subject of the parallel roads of Glenroy still occupies the attention of geologists, and it may induce some one next summer to examine minutely the Dovre terraces and sand-heaps and their relation to the physical geography of the district. I was merely able to make a flying visit to them, which I delayed my party to do, because they caught my eye so forcibly, as we were driving along the valley.