In two previous papers I have set out the conclusions generally held by Northern geologists in regard to the more recent history of the Eastern Baltic, according to which it was once a great enclosed fresh-water lake or sea, the Ancylus lake, which by the breach in the land-bridge connecting Skäne and Denmark was converted into a brackish-water sea, the Litorina sea, which has in turn become less and less saline until it has reached its present condition.

In the first part of this series, p. 313, I referred to the recent invasion of the Eastern Baltic by the Mya arenaria, as first pointed out by Dr. Nathorst. Dr. Petersen has called my attention to an important paper by A. S. Jensen, which has apparently been overlooked by English conchologists, and I propose to condense his results, as they are very noteworthy from their geological lessons.

The shell has hitherto been treated as a typical Arctic shell. Thus Crosse and Debeaux write of its original home: “De l'océan Glacial arctique, qui parait être sa véritable patrie, elle est descendue dans les mers du nord de l'Europe, jusques et y compris la Manche etune partie de nos côtes de l'Océan” (Journ. de Conchologie, ser. III, iii, 254, 1863). Gwyn Jeffreys, in describing the shell, says, “The occurrence of this circumpolar shell-fish so near the tropic of Cancer probably indicates the most southern limit in space of the glacial epoch” (Brit, Conch., iii, 65, 66).

The specimen (Fig. 6), kindly entrusted to me for description by Mr. Howard Fox, consists of the oral skeleton surrounded by portions of the disc and of portions of the five rays, all seen from what is believed to be the ventral or actinal surface, and lying on a fragment of the dark slate of the locality, Epphaven. The skeletal parts being preserved in pyrites, it has proved possible to develop the specimen slightly by washing with weak hydrofluoric acid and then brushing with a soft brush. The specimen is, however, so minute and delicate that this process could not be carried very far.

Through the kindness of my friend Mr. E. T. Newton, F.R.S., of the Geological Survey Museum, Jermyn Street, I was placed, in October, 1902, in correspondence with the Rev. Samuel Couling, M.A., of the English Baptist Mission, Ching-chou-fu, Kiao-chow, North China, who obligingly transmitted to me several fossils which he had obtained from “West Shantung, and south of Tsing-tshou-fu, 36° 40′ N. lat. and 118° 40′ E. long.” He referred me to Richthofen's Atlas, on which the hills where the fossils had been obtained are marked “Mittel und Ober Sinisch”—between Cambrian and Silurian in age.

When revisiting Speeton on the 6th of April, 1905, I was surprised to find that the exposures of Bed (Hunstanton) Chalk on the beach at the locality (about 500 yards east of the mouth of Speeton Beck) where the excellent vertical section described by Mr. W. Hill occurs were almost invisible owing to the accumulation of boulders of white chalk by which they were covered. At length I found a small exposure of Eed Chalk near low water mark and, within 3 or 4 yards to north of it, that is, seawards, I came across a reef of chalk in well-defined beds, each perhaps 6 or 8 inches thick, weathered to a brownish or drab tint. This chalk, when freshly fractured, was hard and white, quite unlike the true Red Chalk, although practically at the same level. The prevailing dip of the white chalk of the reef was from 25° to 28° to W. 40° S. mg. (= W. 57° S. true), and the length of the exposure along the strike, so far as the limited time at my disposal would allow me to observe, was 65 paces (say 55 yards), the width in the direction of dip being 16 paces (say 13½ yards). So far as I have been able to gather, this reef of white chalk to seaward of, and apparently dipping beneath, the Red Chalk has not been described. Four possible explanations of its occurrence may be suggested.

The geological age of these beds has been the subject of much speculation by various geologists. In 1845 Orlebar claimed to have found the Gebel Ahmar Sandstone at No. 3 Station on the Old Post Road to Suez, overlying Miocene beds containing Scutella Zitteli. O. Fraas in 1867 imagined he could trace a gradual passage between the Upper Moqattam and these beds, and concluded, therefore, that they were of marine origin and Lower Oligocene age, as they had undergone the same general earth-movements as the Eocene beds.

Lying in the heart of the gold belt known as the Barkerville District, Hardscrabble Creek was discovered by the pioneer prospectors in 1867, and has ever since been noted for the number of heavy minerals associated with the gold. Galena and various iron minerals were recognized, but the most troublesome was a heavy white substance, which caused great trouble to the miners by packing in the sluice-boxes so tightly that the gold was carried over the firmly set particles by the amount of water required to keep the riffles clean. An investigation by an economic geologist of high standing of some lumps of the alleged mineral showed it to be barium sulphate, and no examination was made of the smaller particles.

A few species of Lamellibranchs were recorded by Messrs. Marr and Koberts from the Trinucleus seticornis Beds of Haverfordwest; and though some new species may now be added to their number with the aid of the numerous specimens collected by Mr. V. M. Turnbull, yet a complete list of the species is at present impossible owing partly to the imperfect condition of many of the fossils and partly to the unsatisfactory state of our knowledge of this class as developed in British Ordovician rocks.

The specimen which forms the subject of the present communication is a fragment of a Nautiloid in the collection of Dr. Wheelton Hind, F.G.S., from the Carboniferous Limestone, Kniveton, Derbyshire, that seems to be referable to Gyrtoceras (Meloceras) apicale. This species, instituted by Dr. Foord in 1898, and based upon examples from St. Doulagh's, co. Dublin, Ireland, was characterized as follows:—

The object of the present paper is to provide a short account of a group of rocks to which the general name of pyroxenite may be given, inasmuch as they are essentially non-felspathic plutonic rocks, free from olivine, and of igneous origin, and with a nearly colourless monoclinic pyroxene as the chief or only constituent of many of the most conspicuous varieties. The exposures are widely distributed in the Central, Ova, and Sabaragamuwa provinces, and probably throughout Ceylon, but are individually of very small extent. The rocks are composed of the minerals diopside, amphibole, phlogopite (or biotite), scapolite, pyrite, sphene, and sometimes felspar, calcite, and spinel; the dominant mineral is the pale green or grey granular diopside, colourless in thin sections: the rocks are often entirely, or almost entirely, composed of this mineral; next in importance are green amphibole (dark in hand-specimens, but very pale in thin sections), and a pale golden-brown phlogopite, which sometimes forms a large proportion of the rock, and in extreme cases the whole bulk of sills or dykes several feet in thickness.

In a former publication I have dealt with the anatomy of Prolagus sardus (Wagn.), from the Sardinian and Corsican Pleistocene, in comparison with that of its Tertiary relatives. The following pages deal with the geographical distribution of Pleistocene Prolagus and its bearing on more general questions.

When Ouvier discovered, in the ossiferous breccia of Corsica, remains of a ‘Lagomys,’ which he believed to be closely related to the Siberian Lagomys alpinus, he also suggested other analogies between the faunas of the two regions—Siberia and Corsica (as well as Sardinia), and commented upon the supposed relationship between the insular Mouflon and the Siberian Argali. Similar views were expressed by B. Wagner.

Pumpelly, Loeard, and Lortet sought to establish a connection between a supposed Corsioan ‘ice-age,’ as attested by the trace of ancient glaciers, and the former existence in the island of a supposed inhabitant of cold regions, the Lagomys corsicanus. Hensel had, however, shown before, in 1856, that the affinities of Lagomys sardus from the Sardinian bone breccia are not with the recent Lagomys (Ogotona), but with a Miocene type, for which he proposed the generic name Myolagus (antedated by Prolagus, Pormel). He was in consequence inclined to assume a Tertiary age for the breccias in which the Prolagus occurred (and, indeed, for the whole of the Mediterranean bone breccias). A similar view has again been brought forward of late years.

I myself pointed out (1) that the Corsican Lagomys likewise belonged to the genus Prolagus, as indeed had already been suspected by Hensel from his inspection of Cuvier's figures; (2) that the Tertiary age of the Corsican and Sardinian breccias could not be upheld, above all, because the mollusca occurring in them, as Loeard bad shown to be the case in the ossiferous breccia of Toga, near Bastia, are still living in the neighbourhood.

Nice.—Among the mammalian remains enumerated by Risso from the bone breccia of the Castle Catinat at Nice, are bones and teeth of ‘Lagomys’. Remains of the same genus have been more recently mentioned by Rivière, from a palæolithic deposit discovered by him in a small cave, Lympia, inside the town of Nice.

Mentone. — On pl. xvii (“Faune des grottes de Menton”), fig. 10, of Rivière's well-known publication, is represented a left mandibular ramus of a “Lagomys d'assez petite taille,” according to the explanation of the plate. In the dimensions, which are by no means small for a member of the family, as well as in the contours of the ramus, it corresponds with the Prolagus from Corsica; it certainly belongs to the latter genus, and not to the recent Ogotona (Lagomys). The text makes no mention of this rodent as occurring in the caves of Mentone, so that further confirmation seemed desirable. This has now been obtained in the most satisfactory manner, Professor Boule having found Prolagus in the “Grotte du Prince,” near Mentone. In his preliminary notice on the results of the excavations, this rodent is stated to occur together with the rabbit, etc., in strata underlying an Upper Quaternary fauna (Rhinoceros tichorhinus, reindeer, ibex, marmot, etc.), and resting on deposits containing a Lower Quaternary fauna (Elephas antiquus, Rhinoceros Mercki, Hippopotamus).

Great interest has been excited, not only in the Transvaal, but throughout the world, by the discovery at the Premier Mine, on Wednesday, the 25th January, 1905, of the largest diamond hitherto known. The stone was found by Mr. Wells, Surface Manager, in the yellow ground about 18 feet from the surface, a brilliant flash of light from a projecting corner having caught his attention. After a preliminary cleaning it weighs 3,024¾ carats. According to Gardner Williams the South African carat is equivalent to 3.174 grains; consequently the diamond weighs 9600.5 grains troy or 1.37 lbs. avoirdupois. Through the courtesy of the Directors of the Company, we have been enabled to make an examination of the stone, with the following result:—Roughly speaking, it measures. 4 by 2½12 by 2 inches; but its size and shape will be best realized by reference to the photographs reproduced on Plates VII and VIII, which represent the diamond from four different points of view and its actual size. These beautiful photographs were taken by Mr. E. H. V. Melvill for the purposes of this description. The stone is bounded by eight surfaces, four of which are faces of the original crystal, and will be referred to in this description under the letters A, B, C, D, and four are cleavage surfaces, the cleavage being of course parallel to the face of the octahedron. In the following description these cleavage surfaces are referred to under the letters E, F, G, H. They are distinguished from the original octahedral faces by greater regularity and smoothness.

Mr. L. Richardson, F.G.S., having informed me that he had seen gravels at a high level on the road leading from Stow-on-the-Wold to Burford, I visited the locality, accompanied by Mr. J. W. Gray, F.G.S. About 3⅓ miles north of Burford, at the corner of the turning to Tangley, we came upon a deposit of clay with northern erratics in a quarry of oolite. As the position of such a formation was unexpected, and might be important, it seems desirable to record the discovery.

Stomatopoba Antiqua was first described and figured by Haime from specimens occurring on Gryphæa in the Lower Lias of France. I have not been able to find any record of an English specimen except that in the Survey memoir on the Lias of England and Wales. But recently several specimens of a Stomatopora resembling S. antiqua, Haime, were found in the collection of the late Mr. E. F. Tomes. The fact that all the specimens were encrusting Gryphæa is remarkable; for though many hundred specimens of various molluscs from the Lower Lias were searched, and of these all sorts of oysters with especial care, Gryphæa was the only form encrusted by Stomatopora.

Detailed examination of the remains of fossil mammals from the fluvio-marine beds (Upper Eocene) of the Fayûm has, in several cases, shown that the number of species of the various genera has been underestimated. This is especially the case with Palœmastodon, of which originally only one species, P. beadnelli, was recognised. Subsequently another form, P. minus, was named, and now it has become necessary to establish at least two other species, to one of which probably by far the greater number of the specimens collected must be referred.

The recent history of the Baltic involves problems of great interest and importance, and promises to afford considerable help in solving the mysteries of the later geological changes in Western Europe. It is therefore worth a closer study than has been extended to it in this country. Perhaps I may be permitted to condense in the Geological Magazine what has been written about it in late years by the Scandinavian geologists, and to add some inferences of my own. I am especially indebted to De Geers and Munthe, the latter of whom has written quite an ideal monograph on one section of the story in the Bulletin of the Geological Institution of the University of Upsala, vol. ii.