There always appears an objection to the agencies by which mountains and hills are formed being designated by such terms as “mountain architecture,” “ mountain building,” etc., leading to the inference that to the deposition of the materials which enter into their composition these elevated regions owe their form and structure. There certainly are mountains which have been built, and some such are at the present time in process of building; but these instances refer only to elevated masses of volcanic origin: they have been constructed as the railway engineer builds his embankments, or, with greater preciseness, as the miner forms the bank at the pit's mouth, by tipping over the rubbish brought from below. To hills and mountains forming volcanic cones the term mountain building is quite correct; the volcano in eruption pouring over its lava, and belching forth scoriæ and ashes, which fall and accumulate around its vent.

In the autumn of 1887, during a stay in North Cornwall, I paid a hasty visit to Tintagel, and took away a few specimens of rocks, without, however, having time or opportunity to examine more than very superficially into their field-relationships.

Next to the metamorphic region of the Northern Highlands there is perhaps no area in Britain where the strata have been so contorted and convulsed as in the great Lower Palæozoic region of the Southern Uplands of Scotland, and it is only by the zonal method of stratigraphy that these complexities can ever be successfully unravelled. So far as the present results of the application of that method enable us to judge, it appears that, underlying all these stratigraphical complexities, there is, in reality, a broad tectonic structure of great simplicity. For, if we make exception, on the one hand, of the lowest strata (the Ballantrae or Arenig rocks), which, as we have seen, only rise to the surface within the limits of the Ballantrae district; and on the other hand of the highest formations (Wenlock-Ludlow), which merely skirt the Upland plateau upon its north-west and south-west flanks, we find that almost the whole of the Lower Palæozoic strata of the Uplands are naturally grouped in two grand lithological terranes, viz. (I.) a Lower Terrane (Moffat Terrane), including strata ranging from the Upper Llandeilo to the Upper Llandovery; and (II.) an Upper Terrane (Gala or Queensberry Terrane), embracing strata generally of Tarannon age.

In his “Geology of North Wales” (p. 102, 2nd ed.), Sir A. Ramsay figures a vertical cross-section of a greenstone dyke, which he describes as running along the cleavage-planes of the slate in the Ffestiniog quarries, and alternately “bulging and thinning off in a rapid succession of oval-shaped masses of 3 or 4 feet in length.” He seems to imply that this is one of the dykes posterior to the disturbance which produced the cleavage of the district. The ordinary post-Carboniferous dykes of North Wales, however, strike nearly at right angles to the cleavage; and further it is not easy to imagine any circumstances attending the intrusion of this one that would account for the phenomenon of alternate thickening and attenuation described. A precisely similar peculiarity is to be seen in ‘Dew's quarry’ at Pen-y-bryn, Nantlle.

In an Appendix to the Explanatory Memoir on Sheets 138 and 139 of the Map of the Geological Survey of Ireland (Dublin, 1888), I have given some notes on the petrographical characters of the igneous rocks of Co. Wicklow. One or two of the facts elicited by an examination of these rocks are sufficiently interesting to deserve a wider circulation.

In May last I visited the Preston Hill Quarry, near Maidstone, in the company of the “Geological Field Class,” conducted by Professor Seeley, F.R.S., and took from it the specimen, the analysis of which is given below. In appearance the rock was a hard, grey, sandstone, containing fine quartz grains disseminated throughout its mass; its sp. gr. ═ 2.685; on the addition of an acid sulphuretted hydrogen was evolved, from the decomposition of calcium sulphide.

In the last two British Association Reports of the Vesuvian Committee, I drew attention to some very large masses of trachyte traversed, at the back of Naples, by the tunnel of the Cumana Railway. A full account of the stratigraphy of these will be deferred until some further excavations, now in progress, are completed. I propose at present merely to describe the earliest-discovered and most striking of these masses.

Mr. Edwards in his beautiful work (Eoc. Moll. p. 311, pl. 32, fig. 2) described a species of Pleurotoma under the title of Pl. turbida, Sol. He regards Pl. colon, Sow., as a synonym, but not Pl. colon, Sow., in Deshayes. In this I think he was mistaken. The species described by Deshayes appears to me different from the Pl. colon, Sow., and identical with the species figured by Solander under the name of Murex turbidus. In the second edition of his work Deshayes says that he “noted this species for mischief,” because it is not found at Soisson, but he retained the name of colon, Sow.