This paper is primarily a record of observations made at Trimmingbam since those recorded in a pamphlet entitled “The Stratigraphy and Fauna of the Trimmingham Chalk.” But as the Polyzoa of the Trimmingham Chalk comprise a remarkably large number of species which appear to be at present undescribed and are very characteristic of this horizon, I have taken this opportunity of describing some of the most prominent of these forms, partly in the hope of directing the attention of other collectors to their range and partly to facilitate the classification of the very large quantity of material I have accumulated. I have also taken this opportunity of giving a list of species from the Chalk between Cromer and Weybourne.

The corries and tarns of the Comeragh Mountains have received but scanty attention at the hands of geologists. In the Memoir of the Geological Survey dealing with this portion of co. Waterford their position and height are mentioned, and reference is made to some of the glacial phenomena in their immediate neighbourhood, but no connected description of the whole group of corries is given. Kinahan, in his “Geology of Ireland” (1878), pp. 245, 310, refers briefly to them, and inclines to the view that they were cut out by the action of the sea on the flanks of the mountains, but that the rock-basins which they frequently contain were excavated by small glaciers. The position of the corries, chiefly on the north and east sides of these mountains, as elsewhere in Ireland, is attributed by him to the preservative action of the ice and snow, which would not melt in them so rapidly (owing to their colder aspect) as on the southern and western slopes, where the corries have been obliterated by denudation effected by ordinary subaerial agents. Carvill Lewis refers to the glaciation of the Comeragh Mountains in several places, remarking that they “show signs of glaciation on their north-east side as high as 1,000 feet, up to which height they are rounded off and drift occurs. Above this they are jagged and contain cwms, glacial lakes, and other evidences of small local glaciers.”

A Small collection of fossils from the Bokkeveld Beds has recently been sent to me for identification by the South African Museum, and some of them have been generously presented to the Sedgwick Museum. Amongst this material it is interesting to find some genera not previously recorded from the Cape and some new species. The majority of the specimens are in the condition of internal casts, and hence present especial difficulties in their determination, so that in a few cases some uncertainty must remain as to the generic position of the fossils. However, I am able to record for the first time from these beds the occurrence of the well-known lamellibranchiate genus Buchiola, and of a shell which may be identified with Nyussa arguta, Hall, of the North American Devonian. The genus Buchiola occurs in argillaceous nodules from the Zwartberg Pass crowded with individuals of the species which I have named B. subpalmata and with a few examples of an undetermined species. No other associated fossils can be recognised in these nodules, but I am informed that an abundant fauna is found in the beds at this locality.

A Great difference of opinion seems to exist among geologists, not only in Britain but also in other countries, in regard to the supposed occurrence of warm Interglacial periods during the age of ice. Those who incline to the views propounded by Adhemar and Croll as to the causes which produced the extraordinary climate of that time naturally look for alternations of cold and warm periods.

Mr. John Smith, of Kilwinning, has been fortunate enough to obtain from the Lower Limestone series of Auchenmade, Ayrshire, a specimen of the left valve of Aviculopecten semicostatus, Portlock, sp., which shows the hinge plate and interior most perfectly preserved. Hitherto a study of the hinge plate of Aviculopecten has been made from specimens which were merely casts of the interior, and consequently it has been impossible to observe that portion of the hinge plate immediately interior to the umbo. The Auchenmade specimen advances our knowledge of the anatomy of the genus, and establishes a character denied for it by its author, M'Coy.

Distribution.—Recent: Red Sea (Klunzinger). Pleistocene, fossil: ? Jebel Zeit (Gregory, 1898); also Old Beach, Camp 7; Wadi Barud, Eastern Egypt. No. J 1789.

After the granites, gneisses, schists, and sediments which make up the Swaziland System had been elevated to form a continental area extending over the northern and western portions of South Africa, denudation began, and the material thus produced was carried to the sea to form the Witwatersrand Beds. The nature of these sediments—they consist of conglomerates, grits, and shales—indicates a marine period with shallow-water conditions, which continued almost uninterruptedly during their deposition. They were accumulated first on a sinking, and then on a rising sea bottom, for the lower beds are composed largely of mud and fine sand, conglomerates only becoming abundant in the upper beds, which were formed in the later portion of the period when the sea had become sufficiently shallow to allow of the accumulation of shingle and gravel. There is evidence in the Southern Transvaal that the land from which the sediments were mainly derived lay to the west, the sea to the east, for the lower Witwatersrand Beds, which consist solely of mudstones and fine sandstones in the east, gradually develop conglomerates with a decreasing amount of shale towards the west.

A Few Gasteropoda were recorded by Messrs. Marr and Roberts from the Trinucleus seticornis Beds, principally from the Redhill stage, but Mr. Tumbull has been fortunate in obtaining a comparatively large number of species. The specimens are not usually well preserved, and the specific or even generic determination of all is not possible with the present material. Some interesting new forms, however, can be detected, and the following list can now be given: —

Much has been written concerning the Archæan rocks from a petrographical point of view, but their structural relations have as a rule received little attention. I do not wish to be understood as overlooking the work that has been done in England, and especially in America, of late, and which has added so much to our knowledge of the older rock groups. But when we come to deal with formations of such high antiquity as those which chiefly concern the geologist in South Central Africa, it becomes evident that we can hope to derive little assistance from the observations that have been made in other quarters of the globe. In the European area there is so great a preponderance of sediments whose nature is obvious, and whose structural relations are only just sufficiently complicated to be interesting, that it is far too common to find the schistose rocks indiscriminately lumped together, with the intrusions that invade them, as “igneous and metamorphic,” whereas in an Archæan area the basis of all stratigraphical work (if I may use such a term) must be the distinction between the igneous rocks and those which owe their proximate characters to metamorphism, whatever their origin may be. We find, in fact, that even where much time and labour has been spent over these rocks they have resulted in so much controversy and confusion that the geologist in a region like Tropical Africa finds it necessary to discard most of his preconceived ideas and start to frame new generalisations for himself. And how important it is to have clear ideas on the subject will be realised when it is considered that in some countries nearly all the rock groups are of Archæan age. Indeed, as I have already had occasion to point out, the European area is probably unique in its vast development of sedimentary as compared with igneous and metamorphic rocks. In Africa the stratified formations may almost be looked upon in the same light as the drift deposits of England. They merely form a superficial coating through which the ‘basement rocks’ of the earth's crust constantly protrude except along the coastal fringe. If we look, for example, at the map accompanying Hatch & Corstorphine's recently issued “Geology of South Africa,” we find separate colours used for eight different sedimentary formations, which range from 5,000 to over 25,000 feet apiece in thickness. Only one of these is known to be of pre-Archæan date, and what are now admitted to be the Cape equivalents of the seven remaining groups are all officially classed as Archæan by the Cape Geological Survey, and it is certain that none are pre-Silurian. It is perhaps necessary to remind the reader that the once popular correlation of the Transvaal rocks with the Palæozoic strata of the Cape is, as was first pointed out by the writer two years ago, quite untenable, and is now thoroughly discredited.

In the maps and memoirs of the Geological Survey of Scotland there is frequent mention of raised beaches at 50 and 100 feet above the present sea - level. Mr. James Geikie, too, in his well-known book on the Great Ice Age, confidently assumes the existence of beaches at these two levels. It is therefore with some degree of reluctance that in the following remarks I venture to question the reality of these supposed beaches; but it will lessen the field of controversy if I confine my observations to theeast side of Scotland. Matters may probably differ somewhat in regard to the west side.

Although the lakes and larger tarns of the English Lake District have been the subject of much discussion and have given rise to a very voluminous literature, comparatively little has been written on the smaller tarns, and especially on those of the very smallest size, which are so abundant in many parts of the district. It seems to us, however, that the smaller ones are quite as deserving of consideration as the larger, since they present similar phenomena, and their interpretation gives rise to similar difficulties.

After visiting in 1905 the excellent exposure of the Permo-Carboniferous Dwyka Conglomerate, containing glacially striated boulders, overlying glacially striated Barberton beds at the foot of Gotshe Mountain in the Vryheid district of Natal, it occurred to me to examine the Permian breccias of the South Devon coast to see whether I could find any evidence of their being of glacial origin.

(xxviii) The road from Llanarmon to Graianryd practically traverses the whole limestone sequence. The following fossils were obtained from the quarry about half a mile north of Llanarmon, by the roadside, where some 20–30 feet of limestone was exposed.

The palæontological succession of the Carboniferous rocks of North Wales is practically identical with the succession in the Pennine area, and to a certain extent with that which obtains in the Bristol-Mendip area.

The various views put forth prior to 1893 to account for the origin of Indian laterites have been clearly and sufficiently discussed in Oldham's edition of Medlicott & Blanford's Manual of the Geology of India (pp. 369 et seq.). Since that year the only contribution of importance to the literature of lateritic genesis in India is a paper by Mr. Thos. H. Holland, F.R.S., the present Director of the Indian Geological Survey, having for its text the conclusions of Bauer. In it the author suggested that laterite might owe its origin to “some lowly organism,” but no sufficient data were advanced in support of the suggestion. Bauer's specimens indicated a certain amount of dehydration in laterites, and this fact, together with the absence of hydration products from certain peridotites in Southern India, was deemed to indicate a general dehydration for the bauxitic laterites of the Deccan. The gibbsite (Al2 O3, 3 H2O) of laterite was supposed to be dehydrated to diaspore (A2 O3, H2O), and it was assumed that “this irregular loss of water is probably the cause of variation in bauxite.”

The author, who has long been engaged on the Palæozoics of West Cornwall, divided the killas extending westward from Gerrans Bay into four groups that formed a natural sequence. Moreover, as they included definite Lower Silurian horizons, as characterized by the fossiliferous quartzite of Carne, these divisions were linked with the Lower Palæozoics. They consist of the Veryan, Portscatho, Falmouth, and Mylor groups. On the latest issues of the old Survey maps the area occupied by the first of these divisions is coloured as Silurian, and the region occupied by the remainder as Devonian. That colouring, however, was not adopted by De la Beche, who surveyed the region, nor was it the result of any subsequent survey of the area. In the original Geological Survey map of Cornwall the killas was separated by De la Beche into two divisions, viz., a grauwacke group and a carbonaceous series. Thus, the former lying below the Culm-measures was undifferentiated for the reason, as explained in his Report, that the progress of geology at that time only warranted the broadest generalizations. He moreover expressed the opinion that the terms Cambrian and Silurian should be restricted to the areas that gave rise to the prolonged researches of Murchison and Sedgwick, and deprecated the extension of that nomenclature to districts that had not received the same detailed investigations. In a later and undated issue of the map the grauwacke group is divided into Devonian and Silurian, presumably by the authority Sir Roderick Murchison. The Devonian colour was not only applied to fossiliferous strata in East and Mid Cornwall, but was extended over the unfossiliferous strata in the west. The Silurian tint, on the other hand, was restricted to a zone that had yielded organic remains. Murchison, however, was of opinion that the older zone extended far beyond those limits into the barren strata coloured as Devonian, and it is evident that the latter tint was adopted as a matter of convenience, as no re-examination of the area seems to have been undertaken. The known Silurian region was confined to the coastal belt between Chapel Point and Gerrans Bay, a boundary connecting those localities admitting of the ready isolation of that zone from the rest of the country. That such a broad generalization, however, was only regarded as provisional may be inferred from the absence of a line on the map between the two divisions. It will be seen, therefore, that the subdivision of the killas, as the result of the recent survey, neither invalidates the map published by De la Beche nor the subsequent conclusions of Murcliison. It has, on the other hand, not only brought their generalizations within more definite limits, but has carried the investigation a step farther by demonstrating the relations between the older and newer Palæozoics of Cornwall.

Many years ago, when discussing the origin of the Menai Straits, attention was drawn by Ramsay to the existence of several other valleys running in the same direction, north-east and south-west. Not only is this the case, however, but the valleys of the dominant system that traverses the plateau of Anglesey have the same trend, ridge and trough alternating with wonderful regularity, as far, at any rate, as Llanerchymedd, a distance of some 12 miles from the Straits.

The collections of Echinoidia described in the following report were made by Messrs. Barron, Beadnell, and Hume during their work for the Egyptian Geological Survey, and were entrusted to me for description by the Director, Captain Lyons, R.E.

During a brief survey of the Inferior Oolite in the neighbourhood of Doulting, Somerset, in 1905, I visited a disused quarry on the hill a mile and a half north of Evercreech, and situated where the boundary-line between the Inferior Oolite and Midford Sands is shown on the Geological Survey Map, Sheet xix. I was surprised to find that instead of the somewhat massive rock exposed in the quarry being Inferior Oolite, it was Marlstone, capped with Upper Lias clays and limestones. Since the section is becoming rapidly overgrown, it appears desirable to record the details obtained for the benefit of those who will survey the district in the future for the New Series Maps.

In the September number of this Magazine Mr. T. O. Bosworth raises some questions with regard to the zoning of the Lower Chalk in general, and of Cambridgeshire in particular. As I am responsible for the subdivision of the Lower Chalk of this country into zones I suppose the matter concerns me more than anyone else.