Mr. A. C. G. Cameron, of the Geological Survey of England and Wales, published in 1893 an account of a boulder of chalk so large that the village of Catworth has been built upon it, while springs arise between it and the clays which underlie the mass. Sir A. Geikie now reports the interesting discovery that “a cake or floor of chalk, lying at the base of the Boulder-clay, may be traced over an area of more than twenty square miles in the west and north of Huntingdonshire and in northern Bedfordshire. It crops out more or less continuously along the brow of the hills under the Boulder-clay and rests on the Oxford Clay. It probably consists of many large sheets of chalk which, at the beginning of the deposit of the Boulder-clay, were transported from the chalk hills lying to the east and north-east.”

The International Rules of Zoological Nomenclature aim at the “elimination of all possibilities of discussion”; and in troubled times like the present, when it is impossible to secure decision on a knotty problem by the International Commission, automatic solution of any nomenclatorial difficulty should be particularly welcome. We all know of certain genera that have caused trouble to revisers because they were based on several species, subsequently found to belong to more than one genus; likewise species have often been based on a number of differing specimens, some of which have in course of time been relegated to other species or genera. Now Opinion 88 claims that the procedure to be followed in such cases is well known, but on this point there appears to be some doubt, and I therefore propose to discuss the two species mentioned in the above title1.

The limestone hills of the Kinta Valley, standing up with white cliff faces from an almost level plain, form a prominent and picturesque feature of this prolific tinfield, and attract attention and present a varying scene as viewed from different points in the valley of the Kinta River. Their mode of origin has been the subject of marked divergence of opinion amongst geologists acquainted with them, as has also their age in relation to the series of metamorphic sediments found in the same valley.

In Plate 1 of professor Owen's invaluable memoir on the Archæopteryx (Phil. Trans. 1863) the fifth vertebra behind the Acetabula is seized upon as the first of the caudal series. In Pl. 3, fig. 5, of the same memoir, we have the delineation of a young Ostrich’s pelvis; and in that figure the first post-femoral joint is marked as the commencement of the true tail; eight such joints being, even in the young bird, embraced by the posterior processes of the iliac bones.

Over the area in question the total thickness of the Chalk (where it can be measured from top to bottom, or nearly so) varies from 623 feet at Streatham to 1146 feet at Norwich, and in the latter case the topmost beds are absent; so that the full thickness, in some parts of Norfolk, may be 1200 feet or more. This figure, however, is exceptional, the nearest to it recorded being 890 at Harwich [this should probably be 895, the Glauconitic basal bed having been called Upper Greensand]. At East Horsley, in Surrey, a thickness of 817 feet has been proved, but generally speaking we find less, and over a large area 700 feet is not reached. It seems that the Chalk thins toward London (where 650 feet may be taken as about the usual thickness), not only from north and south but also from east and west. [It may be well to add the thicknesses proved by other borings outside London. These are as follows, where the borings have passed through the whole formation, from the overlying Tertiary beds to the underlying Upper Greensand or Gault:—Loughton 651 feet, Richmond 670, Cheshunt 681, Chatham and the neighbourhood 680–684, and Winkfield, near Windsor, 725. In sundry places where the topmost beds are missing we have the following:—Bushey (Herts) 686, Chartham (Kent) 735, and Coombs (Suffolk) 817, which last-mentioned should probably be over 820, for the same reason as given above, for increase at Harwich.]

The occurrence of “Sarsen-stones,” or blocks of so-called Druid sandstone, has not, I believe, been generally noticed in this locality, and their position may be of interest to some of your readers, more especially as the extensive working both for Brick-earth and Chalk have obliterated many of the interesting sections for which the pits were celebrated. Grays is well known both for its fine chalk-pits and extensive brick-earth deposits, the latter containing numerous remians of fossil mammalia, associated with land and fresh water mollusca. The sarsen-stones (of which some may be still seen lying about the large chalk-pit), I have noticed during the progress of the workings as occurring on the upper surface of a bed of disturbed chalk, above the solid chalk, and covered by a blackish or carbonaceous clay containing freshwater shells.

The only important fragment of a Pycnodont fish hitherto known from the English Cretaceous Formations, is the portion of head and trunk figured and briefly noticed by Dixon under the name of Gyrodus angustus, Ag. This specimen displays the splenial bones from the oral aspect; some of the vertebral hæmapophyses; and thick scales with a reticulated ornament, covering only the anterior half of the trunk. The ventral ridge-scales also exhibit very conspicuous serrations. The splenial bones are imperfect, but sufficient to show all the essential characters of their oral face; and these elements present the only unique feature in the specimen. It will be observed that, whereas in all Pycnodont splenials hitherto described the dentition reaches the outer border at least in part of its extent, the bone in Gyrodus angustus has a wide toothless outer margin and an attenuated knife-like edge. The two vacuities in this margin shown in Dixon's figure are partly due to accident, partly imaginary, and there is no doubt that the bone forms a continuous whole.

To the earthquake that ruined Lisbon on November 1, 1755, we may trace the great interest in the study of earthquakes which marks the middle of the eighteenth century, though valuable accounts of previous earthquakes had already appeared in the pages of the Philosophical Transactions. During the following year the Royal Society paid the same close attention to this earthquake that it did more than a century later to those of the eruption of Krakatoa. In 1757 an anonymous editor published The History and Philosophy of Earthquakes, in which he gave abstracts of ten memoirs by the “best writers on the subject”—Hooke, Woodward, Buffon, and Stukeley among them—followed by a summary of the observations on the Lisbon earthquake that had been communicated to the Royal Society. These are the principal sources on which Michell depended when he wrote his memoir on the cause and phenomena of earthquakes.

This work was undertaken in an attempt to assess the significance of minor variations in composition and properties of sand samples collected from the same locality and derived from a common source.

In a memoir which was read before the Geological Society of London in 1870, and which was published in the Proceedings of that Society and in the Malta papers, Dr. A. A. Caruana makes mention of a portion of a rib and of a lower jaw of a mammal which were obtained from the Globigerina Limestone at El Kbajer, near Kolla el Baida, in the island of Gozo; and after referring to the fact that no Carnivora had, up to that date, been found in the Maltese Islands, he described the El Kbajer fossils as being “a portion of the lower jaw of a Hyæna with several teeth in situ.”

A large basic sill intrudes the Shineton shale (Cambrian) at Maddocks Hill, east of the Wrekin, near Wellington, Shropshire. An old quarry exposes the contact and reveals that the shale close by has been recrystallized to a hard, compact hornfels, the intensity of alteration decreasing away from the contact. Thin sections show that the metamorphic effect was solely thermal, the rock having been completely recrystallized, and biotite having been generated under conditions of the amphibolite facies. The metamorphism is compared with that brought about by other basic hypabyssal intrusions.

The mineral riebeckite was first discovered by Professor T. G. Bonney in 1882, who, in a paper to the Royal Society describing a series of rock-specimens from the island of Socotra, noticed the occurrence in a granite of a mineral which, though presenting characters common to the hornblende group, he referred doubtfully to tourmaline.

The skeleton figured on Plate XII is that of a small Pliosaur, Peloneustes philarchus, Seeley, sp. This specimen was obtained from the Oxford Clay in the neighbourhood of Peterborough by Mr. A. N. Leeds, F.G.S., to whom the British Museum is indebted for a great series of more or less perfect skeletons of many species of Oxford Clay Reptiles, including the beautifully preserved and nearly complete examples of Cryptocleidus oxoniensis and the remains of Cetiosaurus leedsi, now mounted in the Gallery of Fossil Reptiles. So far as I am aware, this is the first skeleton of a Pliosaur that has been mounted so as to show the true form of the body in those reptiles. All the bones belong to a single individual, but the left-hand paddle and the distal portion of the other paddles being wanting, they have been represented by plaster models made from the paddles of another individual, which are exhibited on the floor of the case. The left ischium has been modelled from that of the opposite side.

THERE has been considerable uncertainty about the true characters of the species Illaenus bowmanni Salter, and many foreign palaeontologists have consequently found it difficult to institute a close comparison of it with other species and have suspected its composite nature. As Holm and Warburg have remarked, the species is badly characterized, and some important critical features, such as the shape of the caudal fascia, are ill-defined or not clearly described in the definitions or well represented in the figures. The poorness of the specimens is largely accountable for these omissions. A recent detailed investigation which the author has been enabled to make of the specimens used by Salter, Portlock, and McCoy in drawing up a definition of the species, together with the examination of many other specimens ascribed to it from the original and other localities, throws some useful light on the subject and helps to clear up some of the obscure points, but it also shows that most of the earlier and current synonymies and references which have been published from time to time are untrustworthy and inaccurate.

Through the great kindness of Professor Suess I have received the full text of his paper on Hot Springs, read before the Congress of Naturforscher und Aerzte held last year in Karlsbad, in which he adduces very strong arguments in favour of their being due to vapours given off from the molten interior of the earth as it gradually cools. I have for a long time been observing the hot springs that occur in the Cape Colony, and had come to the conclusion that they were surface-waters that had sunk deep into the earth's crust, and were returned heated in consequence of their having been in the neighbourhood of potential fusion of the rocks. This latter view I alluded to in a recent paper, and I do not like to have to give up a long-cherished idea before submitting to the public a statement of the reasons that led me to my view of the subject.

Essentially the pores of Megacystis are diplopores, for they are arranged in pairs. This is evident on the inner surface of a plate (E 16169, E 7671). Here each pore-pair lies in a shallow depression, and each pore again lies in a slight depression at the bottom of this (fig. 14). Compare Sinocystis yunnanensis (antea, p. 538).