Summary. Mechanisms forming silicic segregations from basaltic magmas are considered of primary importance when dealing with magmatic problems. However, the processes which give rise to silicic segregations from basaltic magmas are so far obscure. Fortunately, the discovery of spheroidal felsic masses in some basic rocks of Western Sicily throws light on this subject. To clarify the relationships between felsic and basic fractions particular attention has been paid to the interactions which occurred at their contact. Textural evidence indicates that the accretion mechanism of the Sicilian felsic segregations tends to obliterate the silicate liquid immiscibility effects and suggests that the formation of silicic segregations is a consequence of liquid unmixing phenomena.

Before proceeding further with these notes on the geology of The Lizard it will make matters clearer if the sequence of rocks is given as established by the Cornish and other geologists, but I have ventured to introduce modifications which will be explained later:—

Youngest: Kennack granite.

Kennack gneisses, consisting of doleritic and granitic components.

Portable apparatus for obtaining small oriented cores for geophysical or geological purposes is described. It consists of a 34 c.c. two-stroke engine with a 12 ft. long flexible shaft to a drilling head which accommodates the drilling bit and includes a pipe through which coolant from a pressure container may pass. All this weighs under 50 lb. Imperfectly cylindrical specimens may be obtained by hand drilling, or perfect cores with the aid of either of the two rigs described. The first weighs 21 lb. and allows a number of closely spaced specimens from horizontal and inclined outcrops to be obtained. The second weighs 15 lb. and is for obtaining specimens some fixed distance apart from more difficult vertical faces. Magnetic and non-magnetic orienting devices are described. The merits of the method of sampling are briefly discussed.

1. Garnet gneisses of sedimentary origin are described from the oldest group of sediments recognized in Southern Eyre Peninsula, South Australia. The high-grade metamorphism which these rocks have undergone has resulted in the development of felspar, garnet (almandine), sillimanite, and green spinel. 2. The mineralogical association of these constituents is described, and their genetic relations are discussed. 3. A sedimentary origin of these gneisses is attested by their interbanding with undoubted sediments, their mineralogical composition, and lastly by chemical analysis. 4. In the garnet gneisses developed in the Grenville series of North America, notably those of the Adirondack region, and in the province of Quebec, these para-gneisses find their most striking analogues.

Mr. J. V. Harrison has entrusted me with the description of some fossil corals which be has recently collected in Trinidad. They include one remarkable coral which at first sight appeared to be Paleozoic, as its branches had a laminar structure resembling specimens of the Devonian Pachypora cervicornis in which the section has cut bands of corallites at different angles. Examination with a lens at once showed that the coral was septate, and that the resemblance to Pachypora was delusive.

Dr. Croll's “Climate and Time” is perhaps the most important geological work that has appeared in recent years, certainly the most valuable and original that refers to Glacial Geology. It teems with novel and instructive ideas. The part which is best known and has chiefly contributed to its celebrity is the theory, propounded and maintained in the first four chapters, of the causes of the Glacial Epoch. Though the theory met with much opposition at first, it seems now to be gradually gaining belief. Not only are Dr. Croll's views accepted by geologists, but his arguments are quoted in text-books. Now, when Science is used as a means of education, it is of high importance that the reasoning placed before the student should be sound. I propose in this article to examine Dr. Croll's description of the manner in which, according to his views, Glacial Periods have been brought about, to discuss the soundness of his reasoning, and to investigate the actions of the causes which he suggests. Some of the remarks here made are probably originally derived from an able article by Mr. S. V. Wood, jun., in the Geol. Mag. for 1876. The suggestion at the end of the paper is due to Mr. W. M. Hicks, M.A., Fellow of St. John's College.

The second edition of J. W. Dawson's Acadian Geology (1868) contains some notes communicated by C. F. Hartt. One of these, on p. 643, runs as follows:

“Eocystites primçvus, Billings, Coll. Hartt (Fig. 220). The little plate with radiating sculpture, represented somewhat enlarged in the figure, is regarded by Mr. Billings, to whom the specimens have been submitted, as indicating anew genus of Cystideans.”

In this perfunctory manner, without diagnosis or description, was the genus Eocystites founded. Since a named species was mentioned, that species, E. primçvus, must be taken as genotype, and the generic name is thereby validated.

Of the Cirripedes obtained by the late Mr. F. Mockler from the Chalk Marl of Cambridge, two species, Zeugmatolepas mockleri. Withers, and Calantica (Titanolepas) tuberculata, Darwin, sp., have already been described and restorations given. The remaining material consists entirely of disconnected valves, and among these are (1) a number of valves referable to Pollicipes glaber, F. A. Roemer; (2) a few valves of P. rigidus, J. de C. Sowerby, together with some valves of a new species which is probably related to P. rigidus; (3) an important series of valves belonging to several species of Scalpellum allied to S. arcuatum, Darwin, and S. fossula, Darwin; and (4) some valves that do not belong to any of the species already mentioned, and which it will be convenient to describe here.

Mynydd Mawr, about three miles west of Snowdon, is an abrupt rounded hill, 2300 feet high, separating the valleys of Nantlle and Cwellyn. A reference to the maps of the Geological Survey (75 N.E. and N.W.) shows it to be due to an isolated boss of “intrusive hornblende-porphyry ” in the form of a rounded parallelogram, a mile and a half in its longest diagonal. Dr. Hicks has mapped this patch as Pre-Cambrian, and included it in his Arvonian system; but apart from its position, breaking through a regular succession of Cambrian (or Ordovician) rocks, an examination of the junction affords convincing proof of its intrusive character. On the northern flanks of the hill the relations are well exhibited, and the induration and extensive mineralogical alteration of the slate in the vicinity of the boss are very marked. It is indeed by no means easy to determine on the ground the precise point where the hardened, semicrystalline slate gives place to the porphyry.

Before the beginning of this year the only records of the occurrence of fossil marsupials in Western Australia consisted of the account of the discovery of Diprotodon bones in the Kimberley district by Mr. E. T. Hardman, the Government Geologist, in 1882, and the finding of a lower jaw of this animal in 1895 in a gully near Lake Darlot in the Eastern Goldfields by Mr. Arthur, who presented it to this Institution. This jaw was so much weathered that it was valueless except for the fact of its establishing the existence of that marsupial so far inland. The Museum Committee sent an expedition to Lake Darlot in 1898, and in 1908 the Hon. Dr. Hackett sent out at his own cost Mr. Young, who was with Mr. Arthur when he found the jaw in 1895. Both these parties were unsuccessful.

Over most of North-Western Europe the occurrence of river-terrace deposits containing Palæolithic implements has been long known, and the establishment of a sequence of forms among these implements has resulted from the researches of Continental, and especially of French archæologists. With the pioneer work the name of M. Boucher de Perthes, of Amiens, will always be associated. His was the task of convincing unwilling minds of the human workmanship of the ancient flint-weapons found in the gravel-pits of the Somme Valley. For the next great advance we owe a debt of gratitude to another French savant, the late Professor Victor Commont, for his life-work was the taking up of the researches of his predecessor and establishing the sequence of cultural types and their relative chronology.

Having last summer accepted the kind invitation of Mr. J. Gwyn Jeffreys to be his guest on a dredging expedition to these Northern Isles, I was induced, by a request from Sir R. I. Murchison, to look out for any trace of glacial action that I might meet with there. The result of my observations I have thought right to lay before the British Association, apologizing for the meagre story I have to tell. This poverty arises partly from my resolve to devote all time possible to the zoological work, and partly from having seen so small a portion of these islands.

Certain amygdaloid textural features have been observed in a diopside-potash felspar rock within the Lewisian of the Island of Tiree; so far as the writer is aware, such features have not previously been noted in Lewisian rocks.

Evidence as to the genesis of these textures is sparse but they appear to have attained their present nature after the principal metamorphic events which have affected the enclosing rocks.

Since 1857, the occurrence of a gigantic species of the Selachian family Rhinobatidæ in the Lithographic Stone of Bavaria has been well known, and three fine specimens are exhibited in the Munich Museum. No figure, however, appeared until 1887, when Dr. K. A. von Zittel published the illustration he has kindly allowed to be reproduced here; and the only detailed description is that of Wagner, written about thirty years ago. Quite recently, the British Museum has acquired the counterpart of one of the fossils in the Munich collection—a female individual in a remarkable state of preservation; and this is now exhibited in the form of a slab upon the west wall of the Gallery of Fossil Fishes.

So little is known about the geology of the Amazon that it seems worth while recording a few observations made during a recent journey up that river.

In many places in Western Norway we find a lake separated from a fjord by a mile or so of sand and gravel. Looking from the fjord, we see in such a case a series of step terraces, with possibly a high mound at the back, forming a dam at the end of the lake.