modern geologists are accustomed to use this hypothesis in explaining the distribution of fossil fauna and flora. Mr. Harmer shows, on the other hand, that wide-spread climatic changes, sufficient to determine the physical and biologic character of a region, may be produced by variations in the relative position of areas of high and low barometric pressure. The former humid condition of the Sahara and of the Great Basin, the existence of the Mammoth on the shores of the Polar Sea, the non-glaciated Alaskan regions, and the secular variations of the European and American ice-sheets, are factors which have aided the author in determining the areas of low and high barometer and the prevalent storm-tracks of the Pleistocene Epoch. Many meteorological difficulties are avoided by adopting the hypothesis that the maximum glaciation of the eastern and western continents was not contemporaneous. While giving due weight to the older theories of the cause of the Glacial Age as well as to the more recent theories of Prof. Chamberlin and Dr. Ekholm, Mr. Harmer is "inclined to think that the minor variations of the Pleistocene, the pre-historic, and the historic periods may have belonged to one great series of events, and have been alike due to the cause which gives Great Britain its variable seasons at the present day, namely, to alterations in the directions of the prevalent winds."

H. E. G.

6. The Relative Density of Fluid and Solid Magmas.-The question as to whether contraction or expansion takes place when an igneous rock is formed by the solidification of a fluid magma, is one that had been often discussed in connection with volcanic theories. It is generally assumed that the former is the case, and the experiments of Barus, detailed in this Journal ((2), xlii, 498, 1891), are conclusive on the point. Further experiments have been recently carried on by C. DOELTER. He shows that in all the cases investigated by him, as given in the table below, the density of the molten fluid is less than that of the corresponding solid rock; there being a difference of 0.2-0.3 in most cases. In order to obtain accurate results, he remarks that it is necessary to have the molten mass at a temperature considerably above that of fusion, so that its fluidity may be complete. In the case of melanite (lime-iron garnet), for example, which fuses a little above 900, the experiment was tried between 1050 and 1100°. Instead of using a fragment of the same material in testing, a number of different minerals of appropriate densities, and with fusing points considerably above the temperature in question, were adopted. By noting which of these sank and which of them floated in the fluid, the density of the fluid was obtained with a fair degree of accuracy. The accompanying table gives the result for two minerals and five basic rocks. It will be seen that the density of the solidified material in the glassy form is considerably less than that obtained when solidification takes place slowly and the product obtained is more or less crystalline. Furthermore, the last density approximates towards the original

density, while the glassy solid corresponds pretty closely to the fluid in the same direction. These latter results are what were to have been expected.-Jahrb. Min., ii, 141, 1901.

7. Das Siebengebirge am Rhein; by H. LASPEYRES, Mitth. aus dem Min. Institut Univer. Bonn, xii Theil.; Verh. d. nat. Ver. der preuss. Rheinl., lvii Jahr. 1900, Bonn 1901, 8°, pp. 471 with color. geol. map and 23 figs.-This work is a very careful and detailed description of the local geology of the well-known Siebengebirge. Since this is a volcanic group of mountains, so the greater part of the memoir treats of the petrography of the igneous rocks, but in addition the sediments are well described and such topics as the physiography, the local mineralogy, etc. receive adequate treatment. The work of former investigators is considered and a great amount of new material introduced. It is, in fact, a very complete geological hand-book of the region and, together with the excellent detailed map which accompanies it, will be found of great service to every visiting geologist.

L. V. P.

8. New Mineral Names.—A minute examination of the original MANGANOCALCITE of Breithaupt by Breusing has confirmed the results of Rammelsberg and Des Cloizeaux that it is a mixture of a carbonate and a silicate. The author shows further, however, that the silicate belongs to the triclinic system and has the probable composition H,Mn,(SiO,),+H,O. For this manganese silicate the name agnolite (agnolith) is proposed. It is related to inesite, which, however, contains calcium and has a somewhat different ratio.—Jahrb. Min., Beil. Bd. xiii, 265.

MANGANOSPHERITE is a carbonate of iron and manganese not far from the oligonite of Breithaupt. It is described by Busz from the Louise mine near Horhausen, Westerwald, Germany. The composition corresponds to 3FeCO, 2MnCO,. It occurs in globular aggregations and fibrous forms, filling cavities and narrow cracks in basalt; hardness 45 to 5; specific gravity 3.63. Jahrb. Min. ii, 129, 1901.

ESMERALDAITE is a hydrous iron sesquioxide described by A. S. Eakle from Esmeralda county, Nevada. It occurs in pod-shaped masses of a coal-black color, surrounded by a yellowish brown

earthy material consisting of a siliceous limonite. The black mineral has a vitreous luster and is translucent in thin edges; it is brittle, with conchoidal fracture and gives a yellowish brown streak. The hardness is 2.5 and specific gravity 2.578. analysis by W. T. Schaller gave:

Fe3O, H2O (110°) H20 Al,03 CaO P205 S10, Organic (over 110°)

56.14 15.94

An

10.24 5:77 3.35 4:49 2.05 1:37 99.35 If all the substances shown in the analysis, except the Fe,0, and H,O, are considered as impurities, the percentage composition becomes: Fe,0, 68.20, H,O 31.80 = 100. This corresponds to Fe,0, 4H,O.- Univ. Calif., Bull Geol., ii, 315, 1901.

2

9. Mineralogy of California.-Recent issues in the series of the Bulletin of the Department of Geology of the University of California (vol. ii, pp. 315-320 and 327-348) contain contributions to the mineralogy of the State. A. S. EAKLE describes fine crystals of datolite, also pectolite occurring in veins of the serpentine of Fort Point, San Francisco; analyses by W. T. Schaller are added. The same author describes the new hydrated iron sesquioxide, esmeraldaite (see p. 72); the occurrence of coquimbite at the Redington mine, near Knoxville; also crystals of the lead telluride, altaite, with the forms a (100), o (111), ẞ (332) from Sawmill Flat, Tuolumne County.

W. C. BLASDALE shows that the green amphibole of the Coast Range in the neighborhood of Berkeley agrees with actinolite in physical characters though somewhat peculiar in chemical composition, alkalies being present to the amount of 24 per cent. A blue amphibole from the same region comes very near to glaucophane but differs rather widely from the crossite of Palache. Descriptions are also given of tremolite, chlorite, tale and other species.

The Mesa Grande Mountains in San Diego County have recently yielded beautiful crystals of red and green tourmaline, occurring in lepidolite and in the associated quartzite. The crystals are often well terminated and many of them are of considerable size, transparent and of great beauty. The variety rubellite is most common, but many specimens show the characteristic zonal arrangement of color both concentric and in horizontal bands. (See further remarks by Kunz on the Production of Precious Stones in Min. Resources of the U. S. for 1900.)

10. New localities of Nephrite.-A recently issued inaugural dissertation, by A. DIESELDORFF, describes a series of rocks and fossils from Chatham island, as also from D'Urville and Stephens islands, New Zealand. Among other results, the author has made the interesting observation that nephrite occurs in place in serpentine as the mother rock on D'Urville island. This, as he notes, is the first time that nephrite has been definitely located, although obtained so frequently from New Zealand. The nephrite nodules occurring in the serpentine show uralitization,

as proved both by microscopic structure and by composition; in other words, the material is uralite-nephrite. Nephrite was also obtained in rolled masses from the same locality and at other points, but in these cases showed no alteration, so that its composition corresponded closely to normal actinolite.

It is interesting to note in this connection the remarks by G. F. KUNZ, on the recent discovery of nephrite in Siberia. He says:* "This search for nephrite in Siberia was greatly stimulated in 1897 by a command from the imperial house of Russia that material be obtained for the sarcophagus for the remains of the late Alexander III. L. von Jascewski, in charge of the Siberian division of the geological survey of Russia, made three trips to the eastern Ural Mountains for the purpose of discovering larger masses of nephrite than had been known, and if possible, of finding nephrite in place. After thoroughly studying the deposits and obtaining masses of the material in the region of the Onot, which had been visited by Alibert in 1850 and Permikin in 1865, he then wended his way towards the region of the Chara Jalga, in the bed of which river he discovered some masses of nephrite measuring 12 feet in length and 3 feet in width, but even more important than this, he found a ledge of the primitive nephrite of magnificent green color-for the first time recognized in situ in Siberia. Enough of the material was obtained from the bowlders in the streams so that for the past three years the Imperial Lapidary Works at St. Petersburg have been making a small pavilion or canopy to be placed over the tombs of the Czar and his wife. This pavilion or canopy measures 13 feet in height, and is made up entirely of nephrite and rhodonite, of which latter material the entire sarcophagus had already been made for Czar Alexander II."

11. The World's Largest Diamond.-The gigantic diamond found in 1893, at Jagersfontein in South Africa, first called the "Excelsior" and weighing in the rough state 971 carats, was exhibited at the Paris Exposition in 1900 cut as a brilliant and valued perhaps at $2,000,000. It is now called the "Jubilee Diamond," in honor of the celebration of the sixtieth anniversary of the accession of Queen Victoria. G. F. Kunz says in regard to it: "It far surpasses any diamond known, not only in size, but in its faultless perfection of color, luster, and water, and it has been cut with the most skillful modern appliances, so that it is an absolutely peerless gem. The Jubilee diamond weighs 239 French international carats of 205 milligrams. The Orloff of Russia weighs 1944 carats; the Regent of France, 136 carats ; the Imperial, 180 carats, and the Koh-i-nûr, 102 carats. The Orloff, moreover, is a quaint, oriental-cut stone, and if it had been cut as a brilliant would not have weighed over 140 carats. Moreover, it is not flawless. The Regent has a minute flaw, and

*The Production of Precious Stones in 1900, from Mineral Resources of the U. S. for 1900) U. S. Geol. Survey).

Loc. cit.

the Koh-i-nûr has a grayish tinge. As regards purity, cutting, and color the Jubilee is actually perfect, and its form is so symmetrical that when placed on the small truncated apex of its basal pyramid, the cullet, it stands perfectly balanced, though measuring 1 inches in length, 1 in breadth, and 1 inch in depth. As originally found, it was an irregular crystal of gigantic size, 971 carats. The original crystal had a black spot about the center of the mass, but by cleaving it in two this was removed, and the Jubilee diamond was cut from the larger half.

III. ZOOLOGY AND BOTANY.

1. Reports on the Natural History of Porto Rico, Bulletin of the U. S. Fish Commission for 1900.

Among the additional reports received are the following:

The Stony Corals of Porto Rican Waters; by T. W. VAUGHAN. Pages 289-320, 38 plates.-This is a valuable report including descriptions of a considerable number of the common West Indian reef-corals (16 species), and a few from deeper water, illustrated by heliotype reproductions of photographs, except plates i, ii, which are from good drawings of the smaller species. The absence of many of the common West Indian corals is very noticeable and indicates merely that the collections of reefcorals were made without much care or energy, on this expedition. The number should have been at least doubled easily.

Many of the plates are excellent, but some are very unsatisfactory, owing either to the poor quality of the photographs used, or else to faulty reproduction. Among the least satisfactory are those of Orbicella acropora, Favia fragum, Agaricia, sp. and "A. elephantotus." But all might, just as well, have been as good as

the best.

*

The nomenclature adopted is the same as that used by the author in his former paper, on the fossil corals of Curacoa, etc. (1901), and he here repeats the same arguments to sustain his usage. As I have recently printed a paper on the West Indian corals, in which I have criticized some of his conclusions and adopted a different nomenclature, in many cases, it will not be necessary to go into the details of this subject here. But it may be well to call attention to some of the more important points of disagreement, and which relate to common species.

I.-Acropora, 1815, versus Isopora, 1878,-Madrepora authors: It is well known that Linné (Syst. Nat., ed. x, 1758) did not include in his genus Madrepora any recognized species of the Lamarckian genus of that name, but erroneously placed M. muricata (in which several species were included) in his genus Millepora, although it agrees with his definition of Madrepora. * Variations and Nomenclature of Bermudian, West Indian, and Brazilian Reef Corals, with notes on various Indo-Pacific Corals, Trans. Conn. Acad. Science, vol. xi, pp. 63, 168, 26 plates, Dec., 1901.