WITHIN the limits of a brief article such as this must necessarily be, it is impossible to do more than indicate the chief sources of iron-ore supply. The subject is a big one, and of great importance, not only to the British ironmaster, but also to every inhabitant of this country. I am therefore pleased to be able to state that the Federation of Iron and Steel Manufacturers has not only asked the Imperial Mineral Resources Bureau to prepare a summary of the existing information as to the iron-ore supplies of the world, but is also assisting to finance the inquiry. This will mean a more complete survey than is possible to-day.

IT is a fact well known to geologists that the drifts laid down in the peripheral portions of the area affected by the Quaternary Glaciation differ markedly from those developed nearer in to the glacial centres. Beyond, perhaps, a vague suggestion that this may have been due to different climatic conditions during the successive stages of the retreat, no adequate or even partial explanation of the phenomenon has ever been brought forward. Pursuing a line of thought suggested by Dr. Matti Sauramo, in his paper on the glacial retreat in Southern Finland, it now seems possible to offer an explanation based merely on the simple assumption of a greater degree of cold during the maximum of glaciation than obtained during the later stages of the retreat.

Although the process of development of the pygidium in the trilobite has been known since the time of Barrande, its significance does not appear to have been appreciated, and much of the modern speculation on the classification of trilobites is based upon the erroneous idea that those species whose form is most annelidan are most primitive. As a matter of fact, the study of both morphology and ontogeny shows that in this group the large pygidium is primitive and the small one specialized.

THROUGH the kindness of Mr. Henry Woods, I have had the opportunity of examining three blocks of limestone belonging to the Sedgwick Museum at Cambridge, which were collected by the late E. B. Tawney, from the “Chara Bed”, Étage Oeningien, Upper Miocene, at Locle, Jura (Canton Neuchatel, Switzerland). The blocks contain a number of the remains of fruits of a species of Charophyte, which present a feature I had not hitherto observed, and to which I think attention may advantageously be drawn. Before describing this peculiarity, however, it will be desirable to say something as to the conditions of preservation in which such bodies are usually found.

WITHIN the last two years a cutting has been made at the south-east corner of Carrock Fell, a few yards north of the village of Mosedale, for the purpose of obtaining road-metal. This has opened an interesting section near the margin of the intrusion. The rocks exposed comprise two varieties of gabbro and enclosed Eycott lava. Of the two types of gabbro, that next the lava is of the quartz-bearing variety, exhibiting the prevailing dark-green tint in the hand specimen, and carries large flakes of biotite. This is succeeded by the same type of gabbro, but in a highly metamorphosed condition, at once evident in the hand specimen, which is lighter in colour, primarily owing to the decomposition of the felspars.

The investigations which I have carried out in the Ipswich district of Suffolk, and certain discoveries (to be described shortly) made during the past year at Mundesley, Norfolk, have impressed upon my mind the possibility that the ordinary platessiform and batiform palæolithic flint implements found usually in river terrace gravels are older geologically than has been generally imagined. This, however, is not altogether an original opinion, as the late Professor James Geikie, F.R.S., the late Mr. S. B. J. Skertchly, and Mr. A. S. Kennard, basing their views upon evidence other than that upon which I rely, arrived at a similar conclusion. As is well known, it was stated authoritatively many years ago that our English river-valleys containing implementiferous gravel beds were cut through, and are therefore later than the Chalky Boulder-clay.

IN giving graphical expression to the data obtained by mechanical analyses of sediments, the use of curves was found to be very satisfactory. After some consideration the method finally adopted was to mark off along a horizontal abscissa a scale of percentage-weights, from 0 to 100, and upwards, along a vertical ordinate, a scale of grade-size limits from 0 to ·2 mm. and beyond. In cases where the range of the diameters of the grains in a sample is very great it would be necessary to employ a method of reducing the representative lengths, and this has sometimes been done by marking off lengths proportional to the logarithms of the diameters; but in the case of the arenaceous sediments dealt with by the writer, the necessity for this did not arise, and in the curves illustrating this paper, the ordinate lengths shown are directly proportional to the diameters represented. The length along an abscissa, intercepted between the first ordinate and the curve, represents the total percentage weight of the sample which, up to the limit of size specified, has been washed off, and the remaining length signifies the percentage-weight yet remaining to be dealt with. A tendency towards verticality on the part of the curve denotes relative absence or paucity of material of the sizes specified, and, correspondingly, a tendency towards horizontality signifies a preponderance of material of the size specified. Hence, a fine-grained sediment will give a curve occupying the lower part of the diagram, and with increasing coarseness of sediment the curve climbs successively higher and higher. (See Figs. 2, 3, and 6.)

THE small but very interesting collection of Ammonites described in the following pages was obtained during the summer of 1919 by Professor J. W. Gregory, to whom the writer is indebted for permission to study them. There are seven specimens altogether, three of them fragmentary, and all probably originally pyritized, but now converted into limonite. Though immature or fragmentary, all the specimens were seen to have indications of suture-lines, so that their study promised definite results even if, at first sight, it was difficult to place the fauna in the geological sequence. Superficially, there was greater resemblance to the Lower Cretaceous fauna (with Phylloceras of the heterophyllum group and Lytoceras quadrisulcatum) described from East Africa by Krenkel than to the Sequanian fauna of Mombasa, recorded by Dacqué, and a large series of which is preserved in the British Museum (Nat. Hist.).

WITH regard to the laws governing the transport, sorting, and deposition of sediments, much has still to be learned, but one fact emerges clearly from the mass of present data. During the process of transport by water the load undergoes selective treatment, or, in other words, is sorted. The late Dr. G. K. Gilbert, in the course of his important work on the transportation of débris by running water, carried out experiments with mixtures of several grades of detrital material and found that before the slope of the stream had been definitely established (i.e. before the attainment of uniformity of conditions), and especially when low velocities were used, the current tended to sort the débris, building deposits with the coarser part and continuing to transport the finer material. This fact has a special bearing on the study of natural sediments. The state of equilibrium, or of perfect uniformity of conditions, is seldom, if ever, completely realized in nature, and even when approximately reached is not, as a rule, of long duration.

The mechanical constitution of a detrital sedimentary deposit is the aggregate result of the operation of a complex suite of physical laws which govern transport of detrital material by, and its deposition from, water in motion. These physical laws have been elaborately investigated by many workers, and while much remains obscure, important conclusions have been achieved. The detailed examination of the mechanical constitution of the sediments of the geological column has been neglected, although a few pioneer workers have obtained notable results. Sediments of economic value have received attention, but in the realm of pure geology workers have been slow to take up the investigation. Accumulating results indicate, however, that geologists would do well to devote attention to this line of research. Distinctive results are being obtained from sediments, which, even though they may not lend themselves at the present time to complete interpretation, from the point of view of reconstruction of the conditions under which the said deposits were formed, nevertheless bid fair to provide the geologist with another weapon in his armoury. Fluviatile deposits have been found to possess a mechanical constitution distinct from that of estuarine sediments, and the latter are again clearly differentiated, mechanically, from purely marine formations. It may be remarked, too, that the nomenclature in current use applied to the loose sedimentary deposits lacks that element of scientific precision so desirable and necessary if proper progress is to be made. Such terms as “sand”, “clayey sand”, “sandy clay”, and “clay” are at present employed by different writers in different senses, and some system of classification which would give definiteness to the meaning of these and similar terms appears to be urgently called for. The only satisfactory basis for such a classification must be a quantitative one, depending upon mechanical analyses of sediments. When a sufficiently comprehensive collection of comparative data is available it should be a simple matter to devise an adequate scheme for the classification of the loose detrital sediments.

It is well known that the chambers of Cephalopod shells are connected by an organ called the siphuncle, which passes through the septa by the septal necks. Many investigators who have studied these shells have made careful observations on the siphuncle, hoping thereby to throw light on its functions. Such workers as Branco, Blake, Zittel, and Owen, among many others, have written on this problem, while more recently an elaborate study of the structure and constitution of the siphuncle has been made by Grandjean, who gives a detailed account of the organs associated with it. Among the many points established by Grandjean's work, not the least interesting is the fact that the siphuncular tube of Ammonites and Belemnites is composed of calcium phosphate, and not, as had previously been stated, of calcium carbonate. But in spite of Grandjean's careful examination of the less obvious characters of the siphuncle, it appears that certain facts, much more easily observed, have hitherto been overlooked.