1. History.—The genus Cladochonus was founded by Prof. M'Coy in 1847 (Annals Nat. Hist. vol. xx. p. 227) for certain Australian Palæozoic corals with “some relation to Aulopora,” but differing “in their curious erect habit, regular, angular mode of branching, slender, equal stem-like tubes, and abruptly dilated terminal cups bent in nearly opposite directions.”Prof. M'Coy also lays stress upon the thickness of the walls in Cladochonus, and the proportionately small calices, and states (loc. cit., and Ibid. 1849, vol. iii. p. 134) that the curious little corals formerly referred by him to Lamouroux's Jania will fall into this genus, viz. Jania crassa, and Jania bacillaria (Synop. Carb. Limestone Foss. Ireland, 1844, p.197). The Australian species Cladochonus tenuicollis is distinguished by the slenderness of the stolons connecting the calices. In 1851 Messrs. Milne-Edwards and Haime described a genus under the name of Pyrgia (Polyp. Foss. Terr. Pal. p. 310). which has been placed by subsequent writers as a synonym of Cladochnons, and we think with good reason. To their genus they assign the following characters—the corallum is free, pedicellate, with a strong epitheca, very deep calices, and without traces of septal striæ, and they consider that it differs from Aulopora in its simple and free habit. Two species were described, Pyrgia Michelini, Ed. and H., and P. Labechei, Ed. and H. The Janiæ of M'Coy they reserve their opinion on, but C. tenuicollis of the same authour is referred by them to the young of the genus Syringopora (loc. cit. p. 296). Similar views were expressed by them in their subsequent “Monograph of the British Fossil Corals” (pt. 3, Corals from the Perm. Form. and Mounatain Limset. p. 164). 1 and they further describe their Pygria Labechei (loc. cit. p. 166).

The general structure and mode of growth of coral reefs and islands is well understood; but there is one attendant circumstance of considerable geological interest, to which, so far as I am aware, attention has never been called. This is the peculiar stratigraphic relation of the different strata in the reef to their chronological equivalents in the deposits of the surrounding ocean; a relation due to the comparatively rapid growth of the reef as a whole.

Joining a foreign geologist, who was staying here a while last summer on his journey to the North, I followed the old shoreline or sea-level of Bredviken, cut in the solid rock, and extending along the north part of the island of Tromso, near the sound bearing the same name. When, at the end of that line, about Oerendalen, we threw a glance at the low ground beneath, named Skatoeren, this appeared furrowed with a series of natural ditches, stretched horizontally and parallel to the present coast. Seen from above, they were marked very sharply and distinctly. This attracted my attention, the more so as I had often there, and as frequently traversed the plain, without having discovered the fact. We accordingly went down on the low ground to examine the matter more closely, but it did not appear there so distinctly, as might be supposed when seen from above. But after a more searching examination, we succeeded in detecting a series of more or less distinct and parallel furrows. Our time being limited, however, we could make no closer inquiry for the moment; but as I considered the matter worth more minute studying, I returned to the place a few days afterwards.

The remains of a Tortoise from that peculiar fluviatile deposit on the Norfolk coast, known as the “Mundesley River Bed,” have lately been placed in my hands for determination by Mr. C. W. Ewing, of Eaton, near Norwich, and, although the European freshwater tortoise has already been recorded as occurring in a fossil condition in Norfolk (Prof. A. Newton, Ann. and Mag. Nat. Hist., 1862, ser. 3, vol. x. p. 224), yet it seemed desirable that some notice should be taken of this most interesting discovery. The specimen was obtained by Mr. Ewing from the peaty bed in the cliff section at Mundeseley, so long ago as 1863; but it was only quite recently that it was for the first time exhibited, at one of the meetings of the Norwich Science Gossip Club.

Proceeding round the coast from Plymouth.

1. Par. A low range of sand dunes separates the alluvial tracts from the Par sands.

The reference, in my paper on the Calder Valley, to the extensive deposits of boulders and sand which fill up the lower part of the valley, and form a series of long level surfaces, is necessarily very brief. It may assist a proper understanding of the subject, and the point raised in Mr. Dakyns' letter, if I recapitulate, as briefly as possible, the main facts of the case. The river has its source in two or three small streams which rise in the hills on the Lancashire side of the Pennine Anticlinal. These are joined into one stream, and pass along a narrow but deep valley cut at right angles to the range of elevated gritstone hills which form the boundary between Lancashire and Yorkshire. For five or six miles the valley is rarely more than about 200 yards in breadth, and on each side the slopes of the hills are extremely steep, composed of shales, surmounted by a precipitous gritstone escarpment. At Hebden Bridge the Calder is joined by the Hebden, and in its course south-eastwards the valley gradually assumes larger dimensions, and south of Halifax spreads out into extensive level plains, along which the Calder has carved its channel with many devious turnings. On reaching the district from Mirfield to Wakefield these characteristics are still more apparent, its path being amongst the softer beds of the Coal-measures. Below Wakefield to the confluence of the Calder with the Aire at Castleford, the country generally is of a comparatively and un-interesting nature.