In the June issue of the Geological Magazine for 1917 there appears an article by Mr. C. T. Trechmann, D.Sc., F.G.S., on “The Glaciation Controversy in New Zealand”, in which he traverses my views as to the extent of the Pleistocene glaciation of this Dominion. I regret that my recent journeys to the Isle of Pines and Cape Yorke Peninsula and the irregularity of the oversea mails arising from the war conditions have prevented an earlier reply. Mr. Trechmann deals first with the glaciation of the North Island. He says it seems to him that the question of the glaciation of the North Island stands or falls with the origin of the striations on the large andesitic boulder lying near Mangaweka in the Rangitikei Valley (see Plate XIV). He selects these striations as the sole criterion of former glaciation, and argues that “if the scratches are not glacial the boulder is not glacial, and if this boulder is not glacial none of the others are glacial, and the chief evidence for a glaciation of the North Island fails”. As a matter of fact this great striated boulder was not discovered by me till 1915, or some five years after the close of the glaciation controversy between Dr. P. Marshall and myself. Its existence was unknown in 1909. At that time I relied on other evidences of glaciation that Mr. Trechmann passes over with little or no comment.

The rocks which form the subject of this paper were collected by the captain of a whaling vessel belonging to the fleet of Messrs. Salvesen & Co., of Leith, stationed at Leith Harbour, South Georgia. The collection reached me, for description, through the kind offices of Mr. D. Ferguson, Mem. Inst. M.E., who recently visited the island, and who has described its geological features. Two previous collections of rocks from South Georgia have been described by me, one collected by Mr. Ferguson during his visit, the other collected in the same way as the present set.

From the descriptions already given, and from a general survey of the literature of the subject, it is apparent that scheelite is a frequent associate of wolframite in the lodes of magmatic origin. In fact, a certain number of the occurrences already cited, especially in the second part of this paper, might almost as well have been described as scheelite deposits, since the two minerals are found in something like equal quantities. This applies, for example, to a large number of the American and Canadian occurrences, to those of the Malay States, and others. This is only to be expected from general considerations, since gases or solutions containing chemically active tungsten compounds coming in contact with calcareous material would naturally tend to form calcium tungstate. The same applies to lead-bearing minerals; hence in a few instances lead tungstate, stolzite, has been found in association with scheelite. It is of interest to note that scheelite often contains from 1 to 3 per cent of molybdenum. Wolframite and scheelite are often found in lodes and other masses very closely intergrown, and in many cases there is evidence of much pseudomorphism. In some cases scheelite has clearly replaced wolframite, while in other cases the reverse holds. The law governing the paramorphism of these minerals is somewhat obscure, and it is not easy to say anything definite on the subject. In this direction further investigation is required, although the point is not perhaps of much practical importance.

Part III of the Catalogue of the Fossil Cephalopoda in the British Museum (Nat. Hist.), by A. H. Foord and G. C. Crick, was published in 1897. Since then much fresh material has come into my hands and it is now possible to give much more accurate and fuller details of the horizons and localities at which the various species occur. This is of special importance, in view of the fact that the Goniatites can be used as zone indices of the Carboniferous Series from the upper part of the Dibunophyllum beds (D2 of Dr. Vaughan) up to the Middle Coal-measures. This I showed to be the case in my Presidential address to the Yorkshire Naturalists' Union, and published in the Naturalist, April to July, 1909, and elsewhere. Many details have, however, been added since then, and an elaborated and emended table will be published in a forthcoming paper by myself and Dr. Wilmore, F.G.S., on the Carboniferous succession of some Midland areas.

The pith-casts of Calamites are common Coal-measure fossils, sometimes of use in helping to fix the horizon of certain coals. They are, however, notoriously difficult taxonomically, and in several cases there is difference of opinion among authorities both as to the essential characters of a particular type of pith-cast, and also as to what is the most nearly correct name to apply to it. Immense space is still taken up by arguments as to what, exactly, some ancient and often manifestly rough drawing, supposed to represent a type, really depicts—with a view to maintaining a strict priority as regards nomenclature. If the original specimen is now lost, as is not infrequently the case, the guessing still continues. Some workers are not content to start their synonymies chronologically with the next oldest figure, the original of which still survives and the nature of which is agreed to on all hands.

On several occasions during the War, officers on active service in the Near East have found time to collect a few fossils, some of which have been sent to the British Museum. In three cases these were remains of mammals, and these discoveries are of importance as indicating the existence of bone-bearing deposits in localities where they were previously unknown, and where, not improbably, they may prove to be as rich as the well-known bone-beds of Samos and Pikermi.

It may be thought that some apology is due to the readers of this Magazine on the ground of the largely zoological bearing of this paper. But in the opinion of the writer no such apology is necessary. Zoology is palæontology brought up to date, and ontogeny is but a compressed and individualistic type of phylogeny; so that in spirit, though not in matter, this paper is no less appropriate for publication here than its seven predecessors have been. According to Lovén himself, the minute Echinoid which supplies the text for the sequel is to be considered a survivor, not merely of the Holectypoida, but of the most primitive family of that Order—a kind of Lingula or Nucula among Irregular Echinoids. Although one of the main purposes of the following pages ia to offer reasons for disbelieving that contention, nevertheless Pygastrides, as far as the only specimen known is concerned, is for all practical purposes primitively Holectypoid in essential characters. This seeming paradox may be resolved by the anticipatory remark that Lovén's so-called genus is believed to be an early post-larval stage in the development of some more completely Irregular adult form. It is ontogenetically related to that problematical adult, just as the Pygasteridæ must be phylogenetically ancestral to it.

Shells with the external aspect of Bouchardia have been known for some time from the New Zealand Tertiary (Oamaruian), and were first described by Hutton in 1905 under the names of Bouchardia rhizoida and B. tapirina. The correctness of this generic ascription was doubted by von Ihering, who stated that the shells lacked the characteristic external form of Bouchardia. In this, however, von Ihering was mistaken, probably owing to the unsatisfactory nature of Hutton's figures, for these species agree externally with Bouchardia in the very characters which he supposes they lack, viz., the very sharp beak ridges, the more or less straight sides, and the presence of a longitudinal cord over the suture of the deltidial plates. The most characteristic external feature of the shell of Bouchardia is that the sharp beak ridges unite in an apex dorsally of the foramen, i.e. the foramen is epithyrid. In Hutton's supposed Bouchardiæ the foramen is permesothyrid, but almost epithyrid.

The structure of mountain ranges has always been difficult to understand. They often show that peculiarly complicated disturbances of strata have occurred in the process of their formation. Mountain ranges in many stages of dissection are to be seen in various parts of the world; but the better knowledge which their study has furnished us with has not, at the moment, always assisted us in the better understanding of the problem of mountain building.

The area to be described is that part of the Lias outcrop extending from Lincoln southwards to Barrow-on-Soar and Grantham, and includes south-west Lincolnshire and small portions of northeast Leicestershire and east Nottinghamshire (see Map, Fig. 1).

The rocks of this district were mapped by the Geological Survey, and an account of some of them was published in 1885 and 1888; the south-western part of the area has been resurveyed and described in more recent memoirs. A summary of the geology of the area was prepared in 1910 by A. J. Jukes-Browne, but except for these publications the literature is scattered and consists mainly of short papers; details of these are given where they are referred to.

It has long been recognized that, in early Eocene times, while the “Calcaire de Mons” was being deposited in the Belgian area, large tracts of the Upper Chalk were removed by denudation from the south-east of England. The true extent of the unconformity between the Chalk and our oldest Eocene strata is now to be seen only where the Eocene cover yet remains. Even where the Chalk is so covered, the unconformity must have been accentuated to some extent in consequence of the solvent action of percolating carbonated waters, the evidence of which is familiar to us as “pipes” in the Chalk filled with Eocene strata, and the persistent bed of unworn, green-coated flints (“Bull-head” Bed) which everywhere occurs between our lowest Eocenes and the Chalk; but such secondary action is likely to have been more or less uniform throughout the whole area beneath the Tertiary cover.

Let us now turn to the lessons presented by the Mollusca found in the raised beaches of Norway and Western Sweden.

We will now try and picture to ourselves how the circulation of the water was affected by the breach in the land bridge. We have seen in the earlier part of these papers that one of its effects was that the southern and western part of the Baltic became rapidly richer in marine forms. This is because the Straits between Gjedserodde in the island of Falster and Darrserort on the mainland of Mecklenburg form a great barrier to the eastern migration of the marine mollusca, whose species increase greatly in numbers when we pass westward of them. This seems to again point to the fact that the inflow of salt waters into the Baltic from the North Sea passes chiefly through the deeper Belts and not through the shallower Sound, which is the chief outlet of the more brackish Baltic water. On the other hand, the Swedish side of the sea remains poor in fauna until we reach the latitude of the island of Saltholm, due partly to its greater shallowness, which only allows a smaller proportion of the incoming North Sea water to pass.

Since the earlier edition on the geology of Kinta was written much fresh evidence has been brought to light on the subject of the origin of the clays and boulder-clays and the tin-bearing deposits showing bedding at Gopeng. The effect of this evidence has not been to lessen the objections to the glacial hypothesis put forward by myself, but at the same time it still remains the only explanation that meets the facts in a way that can be called at all satisfactory. It may be that long acquaintance with the subject has made me see difficulties in the way of other explanations where in fact no difficulties exist, and my position regarding the question is somewhat akin to that of a doctor versed in tropical medicine who once informed me that the result of many years study of the etiology of beri-beri was that he felt he could raise fatal objections to any theory that had been proposed. I have not seen sufficient reason as yet, however, to change my views on the subject of these clays and boulder-clays. Certain sections to be noted later militate against a glacial origin, but the evidence of these deposits, including those showing bedding at Gopeng, being older than the granite of the Main Range is stronger than it was before. In the following paragraphs I will attempt to give briefly a statement of the points for and against all possible explanations of the peculiarities observed in these important sources of tin-ore.

In 1908 Dr. Rowe published an account of the Chalk of the Isle of Wight with a zonal map in which the zone of Belemnitella mucronata was shown as entirely absent at some points but generally present in substantial thickness. At the two ends of the island actual measurements were made, of 150 feet at Culver Down and 475 feet at the Needles. How much of the latter thickness was measured in the cliffs and how much is made up of somewhat less satisfactory measurements at low tide on weed-covered reefs is not clear, but at any rate there must be well over 300 feet in the cliffs. This figure is sufficient to show how great a ravining of the pre-Tertiary surface of the chalk would be required for the repeated disappearances of the zone as mapped. It seems justifiable to pay some critical attention to the evidence on which such a state of things is alleged.

The detrital matter underlying the Suffolk and N.W. Essex Crags forms an incongruous mass of disrupted local rocks and fossils, supplemented by a few transported boulders of igneous and sedimentary rocks of different ages and mostly small. To these have to be added organic remains of many classes in various conditions of preservation.

Along the narrow belt of Upper Chalk that forms the northern margin of the Vale of Ham (or Shalbourne), a sunken and picturesque lane passes from the village of Inkpen in a direct line to Shalbourne. At a distance of about a quarter of a mile west of the cross-roads in the village (and about the same north-west of the church), the 500 ft. contour crosses this road. On the new series Survey map (Sheet 267) a quarry is marked on the northern side of the road near this point, and a northerly dip of 25° is recorded. The quarry is now almost completely grassed over, but about 100 yards to the east of it (practically on the line of the shaft of the arrow on the map) there is an open road-cutting, giving access to the Chalk, on both sides of the road.

The Imperial Institute, in continuation of its publications with reference to the mineral resources of the Empire, has now issued a map with diagrams indicating the sources within the Empire of the chief metals of commercial importance. The outline map shows the occurrence in each British country of the important metallic ores and also the existence of deposits at present unworked. The locality for each occurrence is not given in detail, but only a general statement, carried out by printing the names of the metals therein found in large type across the face of the country. Asterisks indicate existence of unworked deposits in producing countries, while brackets show the existence of unworked deposits in nonproducing countries. Diagrams are also given, showing in a graphic form the production of metal or ore in each producing country; these statistics are given for the year 1915: since that date many and important changes have occurred, although no doubt it would be difficult, if not impossible, to obtain complete and reliable figures for the later years. The diagrams also show in an instructive manner the relation of the output of the British Empire to those of other countries of the world. The facts here set forth, when carefully studied, afford much food for reflection.

Since Salter, in 1865, published his classification of the species of the genus Homalonotus, no detailed attempt has been made to re-arrange the increased number of species now known into natural groups. Salter was not convinced that his scheme was satisfactory, and appears to have regarded it as largely artificial, though convenient. The divisions instituted or recognized by him bore the names Brongniartia, Salter, 1865 (divided into two sections); Trimerus, Green, 1832; Kænigia, Salter, 1865; Dipleura, Green, 1832; and Burmeisteria, Salter, 1865.

The Sierra Leone, from which the Colony of Sierra Leone takes its name, is a range of palm-covered hills running parallel to the coast (N.N.W.-S.S.E.). It is truncated on the north by the wide mouth of the Roquelle (Rokell) River, which forms the magnificent harbour of Freetown. Towards the south the range terminates at Yawry Bay. The length of the Sierra is therefore about 25 miles and its width, from Kassa Town to Kissy, about 8 miles. On the east side the range descends steeply to the Kwaia plain, from which it is separated by Waterloo Creek. The detachment of the hills from the interior lowland is sufficiently complete to entitle one to speak of the Sierra Leone Peninsula. Freetown is built on the north end of the peninsula, overlooking the harbour, and it straggles up from sea-level to a height of some 800 feet on Wilberforce Hill. The greater part of the peninsula is covered with thick tropical vegetation riglit down to sea-level; and an additional obstacle to geological study is created by the heavy covering of laterite which screens the rocks from observation. In places this laterite mantle is 30 feet thick. But along the northern shore of the peninsula, from Cape Sierra Leone to the mouth of Waterloo Creek, there are nearly continuous exposures of norite, and further useful exposures have been made during the construction of the Hill Railway and along certain of the roads on the hillside. These outcrops make it clear that the whole of the north end of the Sierra is formed of norite, and it would not be surprising to learn that the entire Sierra has the same composition.