The Oceanic beds of Naparima, in Trinidad, contain numerous forms of Foraminifera of great interest, and I propose to make some observations on a few of them These rocks and their contents were described by me in the Journal of the Geological Society of London, 1892 (vol. Xlvii, p. 519). Messrs. Jukes-Browne and Harrison treated of the same subject in the same journal in 1899 (vol. lv, p. 177), and I have given further particulars in the Proceedings of the Zoological Society, 1894 (p. 647), in the Proceedings of the Trinidad Field-Naturalists Club, 1893, and in the GEOLOGICAL MAGAZINE, 1900, p. 322. A few further observations are published in the Proceedings of the Victoria Institue.

The study of Egyptian geology during the last few years has thrown a flood of light on the former extension of the Mediterranean southward in Miocene times. Th. Fuchs, in examining the rich collections from the Cairo-Suez desert and the oasis of Siwah, recognized that the Miocene strata had a close resemblance to those of the Vienna Basin, and corresponded to the Grunder Beds at the base of the second Mediterranean stage, or the lower portion of the Middle Miocene. Later L. H. Mitchell, when studying the neighbourhood of Ras Jemsa and Jebel Zeit in 1887, obtained a number of large oysters, which Meyer-Eyinar recognized as Ostrea crassissima and Ostrea giganlea, and which were regarded as proving the existence of strata of Upper Miocene age along the western border of the Suez Gulf. From these results Blanckenhorn concluded that the Gulf of Suez must have been a Mediterranean bay in Miocene times, and further noted (Zeitsch. Deutsch. Geol. Gesell., Band liii, 1901, p. 79) that characteristic Miocene Pectens, viz. Pecten Sub-Malvinœ, occurred in the collection made by Barron at Abu Sha'ar. He further formed the opinion that all the marine Miocene strata in Egypt were of the age assigned to them by Fuchs (see also Barron & Hume, “Miocene Rocks in Eastern Desert,” Memoir of Egypt. Geol. Surv., 1902, pp. 159–165).

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.

Many ingenious methods and materials have been used for the making of geological models, to show the internal structure and outcrop of a stratified sequence, to furnish maps and lines of section, and to indicate the direction and effects of faults.

Such materials and methods as those of Mr. Sopwith, while most instructive and interesting, are powerless to deal with problems of curved strata, and no material has yet been found by which satisfactory stratigraphical models can be made of folded districts. Such a material must have several properties: —

1. It must be easily made into large plastic sheets of even thickness and of distinguishable colour.

2. It must bend readily and adapt itself sweetly to any surface to which it may be applied.

3. Successive layers must adhere together fairly quickly and quite firmly.

4. The material should set into a rigid but not brittle mass in the end, and yet not be too hard, so that it can be carved readily, or if necessary moulded into any required shape.

5. It would be an advantage if it was cheap.

Casting about for such a substance I have found one which satisfies a good many of these requirements. Not only does it allow of the building up of models out of definite stratigraphical elements in exact imitation of the natural geological structure, but it may possibly be of use in solving certain obscure structural problems. It is also likely to be of considerable use to teachers and students, as models can be built up by or before a class, and it may even have some applications outside geology itself.

The average composition of the igneous rocks is a point of considerable interest in its relation to the problem of their differentiation, and several attempts have been made to solve it by the collation of analyses. Thus, Mr. Clarke estimated the American rocks to average 59.77 per cent. of silica (which may be taken as representative), and Mr. Harker came to very similar conclusions as regards the British rocks, obtaining 58.46 as his figure. The process followed was to add up the results of all the obtainable analyses and take their mean. If each class of rock analysed occupied the same average amount of space—if, for example, the basic intrusions were approximately equal in bulk to the acid ones—such a process would give results of considerable value. As it is, however, very little consideration will show that unless due weight is attached to the relative abundance of the different classes, the results will be very far removed from the truth. Even in Britain, where the development of igneous rocks is comparatively insignificant compared to the sedimentary ones, there are quite enough exposures of the different types to demonstrate this fact. If a geologically coloured map be examined, and the nature of the various patches of igneous rock be enquired into, the immense preponderance of granite becomes obvious, even though the basaltic lavas make a great show on account of their horizontal extension. In fact, the Dartmoor granite mass, if it be assumed to extend to a depth of only one mile, would probably suffice to weigh down the scale against all the other non-granitic igneous rocks combined.

On the rail to Biarritz the roots of the Pyrenees first appear at Dax, and are accompanied by those ophites and thermal springs which are special features of the entire chain. Vast deposits of salt, to whose first development I contributed, have added an important industry to the resources of this ancient capital of Aquœ Tarbelliœ, where the exact harness depicted on Roman medals is still characteristic of every cart. Beneath the existing ditch of the Roman fortifications rock-salt was accidentally discovered by a boring for mineral water, and the salt is now worked at three miles to the south-east, and is indicated by springs for a distance of seven miles. The deposit is known to be about 100 feet in thickness, but is of unknown depth beneath the existing borings.

Along the entire outskirts of both sides of the Pyrenees similar salt deposits abound, and they are often similarly accompanied by igneous rocks.

The salt formation of Dax is distinctly limited by the valley of the Adour, which here ceases to wander among the sands of the plain, and is suddenly and sharply diverted along a tectonic depression, running towards the Pyrenees in a south-west direction. Precisely parallel to this course, in the Cretaceous and Tertiary rocks of the Pyrenees, there runs, at a dozen miles to the north-west, the most remarkable example known of a tectonic valley sunk beneath the ocean. The Gouf de Capbreton, sinking with steep sides to over 3,000 feet beneath the even bottom of the Atlantic skirt, and affording evidence of igneous rocks in its surroundings and in the irregularities of its floor, is a perfect analogue of the neighbouring tectonic portion of the Adour.

It has been suggested to me that a brief résumé of an illustrated article published last year in the Zeitschrift der deutschen geologischen Gesellschaft might be of general interest. The article in question embodies a piece of research work undertaken at the instance and under the direction of Professor Kayser, of Marburg, who during the Summer of 1900 observed in the neighbourhood of Königsberg, not far from Giessen, a bed of rock differing palæontologically and petrographically from the surrounding Culm slate. The rock, a slaty breccia with a considerable limestone content, furnished even on cursory examination a fauna deviating considerably from that generally associated with the Culm. Type-fossils of the Posidonia Slates (the “Culm of Herborn”), such as Posidonia Becheri, Orthoceras striolatum, and Goniatites crenistria, were not met with, but on the other hand Crinoid stems together with fragments of large Producti and of Trilobites of the genua Phillipsia appeared plentiful.

There is no essential difference between Nos. 1, 2, and 3, and No. 4: only differs in being harder, not liable to disintegration by water, and in containing more arenaceous and less argillaceous matter than the other samples. Calcareous matter in all the samples is from 15 to 20 per cent., and consists almost entirely of shells of Foraminifera. There is a considerable amount of sulphur, chiefly as pyrites, greatest perhaps in No. 3, and fragments of Manjak occur in No. 1.