Mr. Thomas Jesson, B.A., F.G.S., of Great Houghton House, Northampton, was lately so fortunate as to discover in the Great Oolite of that county, a new and most interesting example of an Isopodous Crustacean, which, by his kindness, I am permitted to figure and record in the Geological Magazine.

In some parts of the Alps serpentine is by no means a rare rock; indeed it is commoner than some geologists (myself included) once supposed, because much that was formerly comprehended under the term ‘serpentinous schist’ now proves to be true serpentine modified by the effects of pressure.

Owing to the defective character of Sowerby's description and figure of Nautilus elegans, the latter has been variously interpreted, specimens belonging to other species having been frequently referred to it. In the present paper we shall show what is the true N. elegans, tracing the history of the type-specimen, which we have been fortunate enough to identify in the collection of the British Museum. This done, we shall proceed to describe three other species, viz. N. elegantoides, d'Orbigny, N. Atlas, Whiteaves, and N. pseudoelegans, d'Orbigny, all evidently allied to N. elegans, and forming with it a group of species which may be appropriately called the “Group of Nautilus elegans.”

In Professor Henry Drummond's “Tropical Africa,” 8vo. London, 1888, pp. 183–199 are occupied with an interesting “Geological Sketch” of the country between the Zambesi River (about 18° S. Lat.) and the Tanganyika plateau (about 3° S. Lat.), his own observations having been made along a route from Kilimane on the coast, to the Shiré, and up that river, by Lake Shirwa and Lake Nyassa, to Karonga (or Karonga's village) on the north west shore near the end of the lake; and thence through the Uchungu district, for about 70 miles, in a part of the Tanganyika plateau.

In this paper I purpose giving a few examples to show the powerful influences which have been exerted by Earth-movements in producing changes in the rocks, and in obliterating the evidences of succession in some of the disturbed areas in Wales and Shropshire. For a long time past it has been well known that certain changes such as cleavage, etc., have been induced in the rocks in Wales and elsewhere by pressure, but only of late years has the magnitude of the results due to Earth-movements been fully understood.

The proofs of a much greater elevation of the American continent at no very distant geological date, which have been communicated to the Geol. Mag. by Prof. J. W. Spencer and Mr. W. Upham, are very interesting, and Mr. Upham's suggestion that this great elevation occurred in Pliocene and early Pleistocene time is a taking one. He thinks the culmination of the uplift coincided with the Glacial period, and was to a large extent the cause of that period; if he is right, we are forced to infer that there has been a post-Glacial submergence to the extent of over 3000 feet over the whole region, including the Gulf of Mexico. There is, however, a difficulty in this supposition, to which I beg to call Mr. Upham's attention.

I Have elsewhere pointed out the importance of the two factors —(1) the lateral force which produces the metataxic work (quâ cleavage), (2) the resistance offered to the movement of the constituent particles of a rock-mass in the direction of cleavage-dip (in some cases) by the dead weight of the superincumbent mass; the relative value of the two modifying (in the case of a deep-seated rock-mass) the whole metataxic result. Mr. Harker applies the idea in some criticisms of a paper of General MacMahon's on the “Crumpled Culm-measures of Bude ” (See Geol. Mag. April, 1890).