Diamond Region.—The diamond-bearing region in South Africa, as at present known, is chiefly within the valley ofthe Vaal River and some of its tributaries (as the Modder and the Vet); but it is known also to extend down the Orange (Gariep) Valley for a few miles after the junction of its two great branches, the Ky Gariep (Vaal) and the Nu Gariep (CradockRiver). Bloemhof on the Vaal, two hours (12 miles) south-west of Potscherfstroom (Trans-vaal), is the reported locality ofthe most northern diamond-find. Below, for a distance of 370 miles, the plain has yielded diamonds, at several places, on both sides of the river, at Hebron, Klipdrift (near Pniel), Zitzikammsi, Vogelstmis Pan, Sitlacomie's Village, Sikoneli's Village, Nicholson's Farm, Kalk Farm (near Litkatlong), etc.; and on the south side of tie Orange River, they have been found some miles north-west of Hopetown, at Probeerfontein, Roodekop, David's Pan, etc. Diamondsare also said to have been found a few miles east of Fauresmith, on a branch of the Modder, about 100 miles south by east of Litkatlong; also a few miles south of Winburg (also in the Orange River Free State), in the upper drainage of the Vet River, about 80 miles from the Vaal.

Trilobites, appear to have been among the very earliest recognized fossils, not only in this country, but on the Continent, their name having been given them by Walch, in his “Natural History of Petrifactions,” published at Nuremberg a hundred years ago.

In whatever part of the world we live we can readily discover, by ordinary observation, that there are two great forces constantly occupied in remodelling its surface, from year to year, from century to century.

The “Pennystone Ironstone” Nodules of the Coalbrook-dale Coal-field have long been celebrated for their fossil contents yielding, when split open, impressions of Fern-leaves, fruits of Lepidodendron, King-crabs, and the more rare remains of Insects.

The hill of the Great Doward rises above the right bank of the river Wye to the N.W. of the well-known limestone escarpment of Symonds Yat. The section of the Great Doward, geologically considered, is best seen by ascending the hill from theMonmouth road, a quarter of a mile from the village of Whitchurch. The basement beds consist of Upper Old Red Sandstone, which thins out considerably in its Southern strike from the Brecon Vans; and we pass upwards over the Old Red Conglomerate, and the Passage beds of the Upper Yellow Sandstones, while the hill itself is capped by the Lower Limestone shale and the Carboniferous Limestone.

When reading the very interesting article in the “Student” for October last, “On the Deep Sea,” by Dr. Carpenter, I was struck by the description of an Echinidan, which had been dredged up, and which is represented as looking “externally like a sea-egg flattened by pressure; it was about five inches in diameter, and of a brilliant crimson hue. Its test being composed of plates, separated by membrane, instead of being united by suture, was quite flexible, so as to resemble an armour of chain mail rather than the inflexible cuirass with which the ordinary Echinida are invested.” This statement as to the flexibility of the test so corresponds with what I have long suspected to be the case with some, at least, of the Crinoids, that I have been induced carefully to reexamine a large number of specimens, both of heads and columns of fossil, and to make some experiments on recent Crinoids; and I propose now to state shortly the result, and to suggest some points for the consideration of those who may take an interest in such subjects, and who are better qualified than I am, by their knowledge of the animal kingdom, to give an opinion on them.

There are but few men who, having passed many of the best years of their lives in almost constant retirement, have achieved so vast an amount of solid and lasting work, have attained to so high a position amongst their fellow-workers, and the award of whose numerous and well-merited honours has caused greater satisfaction among his scientific brethren than Thomas Davidson, Esq., of Muirhouse, F.R.S., F.G.S., Vice-President, of the Patæontographical Society; Member of the Geological Societies.of France, Edinburgh, and Glasgow; Member étranger de I'lnstitut des Provinces, France, and Linnean Society of Normandy; Imperial Mineralogical Society of St. Petersburg and of the Imperial Society of Naturalists of Moscow; Royal Academies of Belgium and of Bavaria; Société Royale Hollandaise des Sciences, Haarlem; Royal Society of Liège; Academy of St. Louis; American Philosophical Society, Philadelphia; Zoological Society of Vienna; Palæontological Society of Belgium; Hon. Member of the Geologists' Association, the Dudley and Midland Geological and Scientific Society, etc.

Of the immense value of the recent deep-sea soundings there can be no doubt, but whether geologists will side with Dr. Carpenter in the deductions he has attempted to draw from these explorations seems to me a matter of considerable doubt: and I propose to discuss here several difficulties that have occurred to myself on this head. I shall take as my text Dr. Carpenter's last exposition of his views in a letter to Nature of Oct. 27th.

Having had the good fortune to visit Brussels in January last, I availed myself of a few hours' delay to pay my respects to M. E. Dupont, the Director, and M. A. de Borre, the Secretary, of the Museum of Natural History in that city, by whom I was most kindly received and introduced to M. Henri Nyst (whose descriptions of the Tertiary formations of Belgium and tiieir invertebrate fauna have rendered his name familiar to almost every English geologist).

The genus Phaneropleuron was instituted by Professor Huxley, in 1869, for the reception of that singular fish P. Andersoni, from the Upper Devonian Yellow Sandstone of Dura Den, in Fifeshire, which species was also subsequently described by him in the tenth Decade of the Geological Survey, published in 1861. In the present communication 1 have to add a second species, from the Lower Carboniferous strata (Burdiehouse Limestone) of Edinburghshire, by which our knowledge of the genus is thus certainly carried a stage further unwards in the geological series.

Various attempts have been made to measure the positive length of geological periods. Some geologists have sought to determine, roughly, the age of the stratified rocks by calculations based upon their probable thickness and the rate at which they may have been deposited. This method, however, is worthless, because the rates which have been adopted are purely arbitrary. One geologist will take the rate of deposit at a foot in a hundred years, while another will assume it to be a foot in a thousand or perhaps ten thousand years; and, for any reasons that have been assigned, the one rate is just as likely to be correct as the other: for if we examine what is taking place in the ocean bed at the present day, we shall find in some places a foot of sediment laid down in a year, while in other places a foot may not be deposited in a thousand years. The stratified rocks were evidently formed at all possible rates. When we speak of the rate of their formation, we must of course refer to the mean rate; and it is perfectly true that if we knew the thickness of these rocks and the mean rate at which they were deposited, we should have a ready means of determining their positive age. But there appears to be nearly as great uncertainty regarding the thickness of the sedimentary rocks as regarding the rate at which they were formed. No doubt we can roughly estimate their probable maximum thickness; for instance, Professor Ramsay has found, from actual measurement, that the sedimentary formations of Great Britain have a maximum thickness of upwards of 72,000 feet; but all such measurements give us no idea of their mean thickness. What is the mean thickness of the sedimentary rocks of the globe? On this point geology does not afford a definite answer. Whatever the present mean thickness of the sedimentary rocks of our globe may be, it must be small in comparison to the mean thickness of all the sedimentary rocks which have been formed. This is obvious from the fact that the sedimentary rocks of one age are partly formed from the destruction of the sedimentary rocks of former ages. From the Laurentian age down to the present day, the stratified rocks have been undergoing constant denudation.

Of all the “troubles” that afflict the Ironstone miner, few are more perplexing than those known as “wants.” It sometimes happens that in the course of the working a “face” is being carried forward into the ironstone seam, when the miner finds that he has taken out what is apparently the last piece of “stone,” and looks with astonishment at “the blaise where the stone should be.”

The rock described in the following paper is, I believe, new to British petrology; and as the value of microscopical analysis is not yet fully recognized, a detailed description may be acceptable to many readers of the Geological Magazine. The specimens examined were kindly sent to me by Mr. J. A. Phillips, together with a chemical analysis, which, with his permission, is also added.

The Marine Invertebrate Fauna of the Lias would, if one consulted Morris's Catalogue of British Fossils, published in 1854, be regarded as exceedingly poor, especially in certain classes, relative to the thickness of the rocks constituting that system. Thus, I count, eliminating synonyms, 130 species of Cephalopoda, 5 of Gasteropoda, 57 of Conchifera, 37 of Brachiopoda, 1 of Crustacea, 2 of Annelida, 21 of Echinodermata, and 2 of Zoantharia, and if to these we add the fish and other forms of life, we obtain a total of 426 species of plants and animals. But during the lapse of 16 years, this number has been nearly tripled, and to those classes, which were either unrepresented or characterized by a paucity of species, great accessions have been made. Notably, the number of Gasteropoda has risen from 5 to 269; the Conchifera from 57 to 297, the Brachiopoda have been augmented by the addition of 39 species, the Corals now number 67, and the Polyzoa and Sponges, previously unrepresented, now have a place in the list.

In a communication to the Geological Society, “On the formation of Cirques, and their bearing upon theories attributing the excavation of Alpine valleys mainly to the action of Glaciers,” I confined myself to the examination of Cirques in sedimentary strata, and these to a large extent calcareous. I observed this restriction because the most typical examples, so far as I could ascertain, lay in non-crystalline districts, and because my own experience bad not presented to me any very striking instances in other districts. The present brief paper is an attempt to show that, under favourable circumstances, the principles there laid down may also be applied to regions wherein crystalline rock exists.

We are indebted for the material from which the following notes have been compiled to Principal Dawson, of Montreal, and to the Secretary of the Portland Society of Natural History, to whom our best thanks are due for the opportunity thus afforded us of comparing the fossils of the North American Clay Beds with those of our own country. By carefully washing theclays kindly forwarded to us, we have obtained many specimens in excellent condition for examination.

1. Introductory.—The fragmentary evidence attesting the presence of former tenants of our globe is just sufficiently tantalizing to permit of glimpses of bygone forms to be evoked; and what is lacking in the relics themselves is supplied by the imagination or reasoned out by the aid of existing forms. Palæontology, in truth, is based as yet on a narrow but solid foundation of fact, propped up by much that is uncertain or unstable, which future time must test, try,—accept, or reject. For this reason all adventitious drapery thrown around the remnants of the departed requires to undergo a close scrutiny of its genuineness; and no seeming fittingness can save it from the ruth- less hands of succeeding inquirers should any counterfeit be detected.

Just out of Seaford the Chalk rises sharply from beneath the sand of the Woolwich Beds, on an outlier of which the small town is buUt. The dip however soon lessens, until the Chalk is flat, with slight waves. Some of the layers of flint are continuous, and some nearly so, but most are not continuous, and they are rather closer together in the lower part of the cliff. There are a few thin beds of hard chalk, and at the top a capping of “clay-with-flints.”