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.

During a visit to Stockholm last spring, Prof. Gustav Lindström kindly permitted the writer to examine the series of remains of Palöozoic fishes obtained from the Devonian of Spitzbergen by Dr. A. G. Nathorst, during the Swedish Geological Expedition in 1882. Some of the more prominent specimens have already been briefly noticed, with figures, by Prof. Ray Lankester; but the collection is worthy of a more detailed comparative study than that to which it has hitherto been subjected, and among the undescribed specimens most readily identified is a small fossil indistinguishable from the so-called “intermandibular arch” or “presymphysial bone” of Onychodus. Through the kindness of Prof. Lindström, this specimen has been forwarded to the British Museum for examination, and it forms the subject of the following remarks.

During the summer I visited Hof with Professor Nicholson, mainly in order to examine the Graptolite-bearing shales of the surrounding region. These we found to be far from rich in fossils, and the principal fossil-bearing localities were remote from one another. Under such circumstances little could have been accomplished, but for the kindness of Herr Glass, of Hof, who allowed us to examine his fine collection of fossils from the district. To him I would tender my best thanks, as also to Prof. Geinitz, who not only permitted me to examine his rich collection of Graptolites from the Thüringerwald preserved in the Dresden Museum, but also devoted some of his valuable time to me.

For a full account of the Lower Palæozoic rocks of the region under consideration, I may refer to Prof. Gümbel's exhaustive “Geognostiche Beschreibung des Fichtelgebirges mit dem Frankenwalde und dem Westlichen Vorlande.”

As early as the times of Descrates (1668) and Newton (1681), the “ settling and shrinking of the whole globe after the upper regions or surface began to be hard,”2 was held a sufficient cause for the formation of mountain-chains. Following the growth of our knowledge of mountain-structure, the contraction theory has been rediscovered several times in the present century. It has been worked out in great detail by Élie de Beaumont, Prevost, Delabeche and others; but, above all, by J. D. Dana, the real founder of the theory, in an admirable series of papers extending over the last forty-two years.

Leaving its details out of account, the fundamental idea in the contraction theory may be stated as follows: The whole earth was originally at a high temperature throughout, its present distribution of temperature being the result of cooling since the initial epoch.

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.

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.

Mr. Ami's interesting discovery has already been announced in a letter addressed to Mr. A. H. Foord, F.G.S., published in this Magazine (October, 1888). Mr. Ami now supplies a “Note” on the precise geological position of the beds in which the Turrilepas was found. Want of space, however, precludes us from giving the whole of his detailed observations, which are accompanied by a sketch section, here reproduced:—

The following is a summary of Mr. Ami's “Note.”

The Turrilepas was found in a band of bituminous limestone cropping out on the right bank of the Rideau River, at the Rifle Range, near Ottawa. The precise position of the beds (Lower Utica = about the lower part of the Bala Series), was ascertained by means of their fossil contents, which include an interesting Brachiopod—Siphonotreta Scotica, identified and named by the late Dr. T. Davidson, F.R.S.

At the Meeting of the British Association in 1886, a facetted and striated pebble from the Salt Range, Punjab, was exhibited and described, by A. B. Wynne, F.G.S. Another and larger one was presented by Dr. W. T. Blanford, F.R.S.

During the discussion that ensued, the question was considered whether the stones had received their shapes from the action of windblown sand. Having made a special study of sand-carving in a favourable region, the writer became interested in the subject, and with a view to compare the Punjab stones with the sand-facetted rockfragments so common in various parts of America, wrote to Dr. Blanford in order to obtain specimens of the stones in question. By the kindness of Dr. Blanford and Mr. Wynne, plaster casts of both the specimens described by them have been sent to me.