Zoarium always unilaminate, nearly always adherent.

Zoœcia broad, length ·65–·8 mm., breadth ·45–·55 mm., aperture primarily semicircular but tending to quadrangular by thickening of the upper lip, and with a semicircular collar, the two ends of which are expanded into large perforated spine bases: the arched front wall springs from the inside of the side walls and is pierced along its edge by a row of large pores, and at a short distance inside this row by a row of smaller pores in fairly close correspondence with the outer row; the centre of the front wall is pierced by a very variable number of fine pores, which sometimes give clear indications of a third row corresponding to the two outer ones; the zoœcia always have common side walls of considerable width; in immature stages (Fig. 1) the front walls rise high above the side walls, and small beak-shaped avicularia are scattered irregularly between them; in a further stage of development (Fig. 2) the side walls are greatly thickened and raised above the front walls, absorbing the avicularia, and the perforated spine bases at the corners of the aperture grow inwards until they meet, and are fused into a stout bar across the aperture, so qualifying the species for admission to the Steginoporidæ; in the stage of maximum development (Fig. 3) the bar develops a stout denticle in the middle of the lower edge.

In the centre of Ross-shire, to the west and north-west of Ben Wyvis, there are large intrusive masses of granite gneiss lying in the midst of the sedimentary Moine schists. They have a N.N.E. strike and extend over a tract of country about 20 miles in length, from Loch Luichart, near Garve Station (Dingwall and Skye line), to Carn Bhren, within 3½ miles of Ardgay Station (Inverness and Wick line). A coarse augen gneiss with large elliptical eyes of pink orthoclase or perthite, sometimes 2 inches long, is the principal rock, but a finer-grained granite gneiss also occupies considerable areas, especially in the region of Carn Chuinneag (see Map, Fig. 1). Boulders of the augen gneiss have been widely distributed by ice, and are common on the shores of the Moray Firth, etc. For that reason the “Inchbae augen gneiss” has long been familiar to geologists, though little was known about the parent mass, except that gneisses of this type were exposed on the high road between Garve and Ullapool, particularly in the lower part of Strath Rannoch.

It has been known for more, than a hundred years past that a small tract of Upper Carboniferous rocks occurs in North-West Gloucestershire, between May Hill and the Malverns. The beds crop out in the neighbourhood of Newent, a village lying some ten miles to the north-west of Gloucester. The field, however, is almost entirely concealed beneath Triassic rocks. The measures are productive, and have been worked at various periods on a small scale, though the greater portion of the basin remains to this day unexplored.

The article which appeared by Dr. Ball in the February number of the Geological Magazine (pp. 71–6), strongly urging the origin of the Egyptian Nile Valley as due to erosion rather than faulting, is the first public expression of a widespread feeling that the familiar rift theory is based on comparatively feeble foundations, and either requires strengthening or withdrawal. It must be remembered that when the Geological Survey of Egypt commenced its operations in 1896 the relation of deep African depressions to rifts was an accepted theory which had been found applicable in a number of striking instances. As one who has studied portions of the Nile Valley and the neighbouring deserts of Egypt for some years, I submit these few remarks, adopting a somewhat more personal point of view than is usual in papers of this nature, not from a desire for controversy, but because the subject is one worthy of discussion.

The object of this paper is to place on record the occurrence of olivine nodules in a British basalt which, though closely allied in structure to some of the Tertiary basalts of the Continent, belongs undoubtedly to the Carboniferous age. Olivine nodules frequently occur in the Continental basalts and have been considered by some writers as inclusions of peridotites, but by others as segregations from the magma.

It may seem strange to dwellers in this country under its present conditions to speak of relics of a Glacial Period being visible in the plains of the Ganges Valley, where the mean annual average temperature is about 77˚ F. and we all know what the maximum may rise to; and at the outset I must guard against misapprehension by saying that I do not mean to imply, by the title of my discourse, that the plains of India were ever, within geologically recent times, covered with snow and ice. We have evidence, it is true, that in long distant ages, at the beginning of the period that saw the filling up of the valleys of the old Gondwana continent, part of which still exists as the Peninsula of India, that is to say, when the deposits of clay and sandstone, supporting a luxuriant vegetation, now transformed into the coal of Raniganj and other localities, were beginning to be laid down, the higher ground of the Peninsula was under snow and ice, and that glaciers descended into the low ground and probably sent off icebergs into the surrounding seas. Traces of these events, which took place in what is known to geologists as the Talchir Period, even the old rock-floors grooved and striated by the passage over them of fragments of rock embedded in moving ice, have been found at the base of the Coal-measures in the Central Provinces and in Rajputana, while a bed containing striated and polished boulders, exhibiting unmistakable evidence of ice action, is known in the Salt Range of the Punjab. But with these, and with traces of what may prove to have been a still older ice age, of which Sir T. Holland brought some evidence before this Society in August, 1908, discovered by him near Simla, I do not propose to deal on the present occasion.

“The Indus has been eroding severely on the right bank, about 30 miles higher up than the erosion which I told you threatened the railway at Rohri on the left bank. The chord of the curve of the bank attacked was over 2¼ miles long, and the erosion at the apex would be as much as 100 feet a day: it amounted to 3400 feet in forty days. It has given us a good deal of trouble, as with a big breach here the water would travel 120 miles before it would be forced back to the river by the hills on the edge of the deltaic deposits, and loop embankments of great length had hastily to be constructed behind the portions of the flood-embankments threatened with erosion. We succeeded with two loops, but with the third had a breach in the weak new loop; the men have been able to keep it from spreading more than 700 feet wide, and have since got it nearly under control.

The aim of this paper is to offer an explanation of the phenomena intimately related to the sculpturings of the Chalk Downs in the district under review, namely:—

(1)The Dry Chalk Valleys.

(2)The River System of the Wealden area, as far as it relates to the Chalk Downs.

(3)Incidentally, the Denudation of the Wealden area.

This brief article is necessitated by the impossibility of procuring photographs and rock sections in time for incorporation in my former paper in the January number of the Geological Magazine, pp. 6–15.

My next four species are linked together by their avicularia, which in each case have the side walls infolded over a long deep-set area.

A contribution by Messrs. Horwood & Wade to the Geological Magazine for November, 1909, calls attention (p. 505) to certain papers by me on the relation between the gneisses and schists and the later granites of Southern Nigeria.

In August, 1841, Professor J. D. Forbes, in company with Professor Agassiz and Mr. Heath, spent some time upon the Lower Glacier of the Aar, and Forbes states that it was then for the first time that he noticed the veined or ribboned structure of glaciers. Although the description given in the communication he made to the Royal Society of Edinburgh in December of the same year is most interesting, he does not state clearly how the structure is related to the glacier grains of which the ice streams are built up.

The British Museum collection has lately been enriched by two Cephalopods from the Chalk of Lincolnshire that seem to be worthy of notice; one being a new species of Pachydiscus (P. farmeryi), the other being referable to the genus Heteroceras.

Zoœcia generally elongated, but very variable in shape and dimensions; length of area ·68 to ·48 mm., breadth of area ·36 to ·2 mm.; no fornt wall, side walls very low, with a further depression at the head of the zoœcium, and furnished all round with slender buttresses, which are much more easily distinguished in the upper part of the zoœcium, owing to their greater size and Projection there, than in the lower Part.

Those who are acquainted with the detailed zoning of the Upper Lias and Inferior Oolite of the Cotteswold Hills have long desired to know the precise date of the Upper-Lias deposit at Leckhampton Hill, Cheltenham, upon which the Inferior Oolite rests. At last the desired-for information is to hand. The Inferior Oolite at Leckhampton Hill rests directly upon the Variabilis-Beds of the Upper Lias.

When last year I had an opportunity of examining a few rocks and fossils from the limestone of Creechbarrow Hill, which the late Mr. W. H. Hudleston considered of Bagshot age, I at once suspected that they belonged to the Bembridge Limestone. Upon my pointing this out to Professor Hughes he requested me to go down to examine the ground, which I did in November of last year, but I found only the same fossils which Mr. Hudleston had recorded, namely, Melanopsis and Paludina. On my return to Cambridge I expressed the opinion that better evidence would probably be obtained if a few openings were made here and there, and the Professor arranged that I should carry out a further examination of the area at a more convenient season. This I have done, and I now offer the results of my further researches.

It is believed that the ancient Britons and the Welsh were fully aware of the precious metal which lay among their hills. Three Welsh chieftains are known to have possessed chariots of gold, and it is inferred that this gold was derived from mines which the Welsh worked at an early date. Many gold ornaments have from time to time been unearthed, and as their style differs entirely from that customary at the early Christian period, they are believed to belong to a time long anterior to that of Christianity. Again, it is known that the Romans under Julius Cæsar worked minerals in various parts of Britain, and there are many evidences of Roman mine-workings where gold must have been the principal, if not the sole, object of search. One of the most remarkable of these is outside Merionethshire, at Gogofau, near Pumpsaint, in Carmarthenshire, where the traces of Roman occupancy are undoubted. Another locality, this time in Merionethshire, is reported by Ramsay (12, p. 64) as on the banks of the Allt-y-Wenallt.

Novak considered this form within the range of variation of Cellepora depressa, Hag., but Canu recognizes it as a Rhagasostoma. It appears to be so closely related to a very distinct and persistent form which is very abundant and characteristic at Trimingham that I do not like to treat them as anything but two forms of a single hitherto unnamed species, and the form admirably figured by Novak must of course be the type of the species.

In a previous paper it was shown that one prominent topographical feature of the Tarntal district, the great cirque called the ‘Grübl’,. could be explained as the effect of erosion by a short icetongue which formed when the snow-line persisted for a time at about 2400 metres above sea-level. The basin-shaped hollow of the Upper Tarntal was held to be due to another stand of the snow-limit at 2650 metres. It remains to be seen whether these conclusions are supported by evidence of a similar nature collected over a wider area.

The Orthopteron wing which forms the subject of the present paper was obtained by Mr. David Davies from a dark-blue shale, about 10 feet in thickness, overlying the No. 2 Rhondda coal-seam in Clydach Vale (see Plate XV). The shale decreases to the east, dying out wholly 2 miles beyond the colliery, giving place to sandstone. I am indebted to Mr. Davies for the opportunity of describing the specimen.