From time to time I have accumulated a large number of results obtained in identifying precious stones by means of their specific gravity. From these results I have selected about 70, which will be found arranged below. The observations have been made with care, and, where no temperature is given, at 15° 5 C.; an asterisk denotes those determinations in which a very accurate assay balance by Oertling was used, and in which the specimens were immersed in alcohol, not in water. In these latter determinations any error would be confined to the third place of decimals.

The genus Brachymetopus was founded by McCoy in 1847, and the generic characters were drawn from the Australian species Br. Strzeleckii, McCoy, which was at the same time described. The specific characters of this form were very briefly given, the leading features having been mentioned in the diagnosis of the genus. Dr. Henry Woodward in 1884 gave a new summary of the generic characters differing somewhat from that originally furnished by McCoy, being modified in such a way as to include the European or British species, Br. ouralicus, De Vern., Br. Maccoyi, Portl., Br. discors, McCoy, and Br. hibernicus, Woodw. The original type-specimens of Br. Strzeleckii used by McCoy (op. cit.) in drawing up the description of the genus, and figured by him at the same time, are in the Woodwardian Museum, to which they were presented in the year 1844 by the Rev. W. B. Clarke. They come from the Carboniferous Shale of Dunvegan, New South Wales. The specimens comprise three complete head-shields, two of which are hollow impressions and one a cast, and portions of three or four others; there are also three casts of complete pygidia, one perfect impression, and fragments of two others. This material demands a fuller description of the specific characters than McCoy furnished, particularly as this type-form of Brachymetopus shows features differing in several respects from those of the better known European species ascribed to the same genus. McCoy's description (op. cit.) of the species was as follows:—

“Glabella widest at the base, with one very minute, obscurely marked, cephalothoracic furrow at the base on each side; all the segments of the pygidium with an irregularly tuberculated ridge along the middle; lateral segments forming large tubercles where they join the thickened limb, opposite each of which is a short slender spine projecting from the margin”.

As I have paid some attention to the Eskers of Ireland, perhaps I may be allowed to make a few notes on the papers of Mr. F. J. Jamieson recently read before the Geological Society of London, and the letter of M. Jespersen that appeared in the Geol. Mag. for December, 1874. These observers put forward the theory (if I understand them rightly) that these peouliar ridges of shingle, gravel, and sand may be in part glacial, they having been accumulated as marginal fringes to the different stages of the ice-cap that at one time covered the northern portion of the Continent of Europe, as it intermittingly retreated. This suggestion seems worthy of consideration, as possibly, if the ice-cap had an intermittent retrogression, there would be fringes or ridges of shingle, gravel, and sand marking each rest, formed of the detritus from each successive portion of the ice that disappeared; but such accumulations should be at different altitudes, and being carried by water off the ice, and deposited successively at its edge, should be stratified outwards,—or if the margin was retreating, they would be jumbled together.

Three are a number of simple Cheilostomata which develop avicularia distinctly larger than the zoœcia and more or less constricted in the middle by prominent masses apparently due to infolds of the side walls. Eschara Lesueuri, Hag., sp., is a good example, and others have been figured by D'Orbigny. Similar forms are not uncommon in the English Chalk, but it is curious that all the foreign forms seem to be of branching Biflustrine habit, while all the English species I have yet met with form unilaminate sheets.

The question of the origin of Eozoon Canadense has been recently revived in an important and most interesting paper on a similar structure in blocks of limestone ejected from Vesuvius. The writers, however, of that paper evidently found that more information existed as to the microscopic structure of the Canadian Eozoon than as to its mode of occurrence, so that a few notes on this subject may be of some use as a contribution to the discussion. I visited one of the most noted localities for Eozoon—Côte St. Pierre—in 1884, when I had the inestimable advantage of being conducted by Sir J. W. Dawson, to whose unwearied kindness and hospitality I was so often indebted during my stay in Canada. I made careful notes and rough sketches of what I saw, collected a fair suite of specimens, and paid especial attention to the relation of the structure to other parts of the rock-masses. Upon the question of the origin of Eozoon I do not purpose to enter: I shall restrict myself to stating facts of which, as it seems to me, account must be taken in all attempts to interpret this extraordinary structure.

The creature which forms the subject of the present communication is the same as that which was described as Asterolepis by Hugh Miller in his “Footprints of the Creator,” and consequently its remains are at present better known to British geologists and palæontologists under that name. Why, then, alter a name which we have used so long? is a question likely to be asked by those who have not critically studied the complicated mesh in which the synonymy of the name “Asterolepis” is entangled.

If the line passing through those three grand centres of volcanic action—Vultur, Vesuvius, and Epomeo—be produced to the westward, it will strike the very interesting igneous masses of the Ponza Islands. These insignificant islands, which, from the early Roman times down to the present day, have figured in history only as places of banishment for criminals, possess for the geologist the very highest interest. This is due not only to the wonderful characters of the rock-masses which compose them, but also to the admirable manner in which these are exposed to our study by the extreme denudation to which they have been subjected.

SOME time ago Mr. Charles Edmonds provided me with a number of sandstones of Carboniferous age from West Cumberland to compare with the sandstones of the Peel Series in the Isle of Man. These specimens proved to have an interest peculiar to themselves which it is the purpose of this note to describe.

The subject of this paper is a group of three intrusive masses of igneous rock, possibly laccolitic in their origin, whose outcrops are situated within a radius of a mile from the village of Llanfairfechan, on the north coast of Carnarvonshire.

AT certain levels in the Coal Measures of North Wales a flood of fish scales and bones occurs, to the exclusion of almost every other fossil; at others only an isolated scale or tooth is seen. The area appears to be especially rich in fish remains, though possibly this is due to inadequate collecting in other areas. A summary of the succession in the Flintshire and Denbighshire portions of the coalfield is shown in the diagram on p. 483, while the area dealt with is shown on the map (p. 482).

During the past summer I had the pleasure of studying the Miocene and Upper Oligocene beds at various places in the Bordelais, mostly under the guidance of the amiable Professor of Geology in the Faculté des Sciences in Bordeaux, Monsieur E. Fallot; and the following notes are mainly intended to give an idea of the present appearance of the classical Miocene sections in that district, and to say something concerning their classification and that of the other Tertiary beds of the Gironde, following the most recent researches on the subject.

During the years 1918–1931, there were 270 earthquakes with unusually deep foci, 167 in the Northern Hemisphere, 101 in the Southern, and two with epicentres on the equator. The normal depth of focus is assumed to be about 50 km. or ·008 of the earth's radius. The focal depths of the above earthquakes range from ·005 to ·090 of the earth's radius below the normal depth, or from 50 to 380 miles beneath the surface. Throughout this paper, the depth, when given in terms of the earth's radius, is referred to the normal depth; when given in miles, to the surface of the earth.