= = sion of dark-colored glass, bronzite in broken fragments and also in spherules with a fine fibrous structure, broken plagioclase, rich in black inclusions lying parallel to the twining planes, and, finally, patches of an isotropic mineral, probably maskelynite. It contains the following constituents: nickeliferous iron, 17.16 per cent.; mineral portion, 82.84 per cent. The iron yielded upon analysis, Fe=91.32 per cent.; Ni 8.04; Co= 0.60; Cu=0.04. The mineral portion was divided into two parts, one soluble in hydrochloric acid yielded, FeS 6.08; NiS =0.62; and 48.85 per cent. silicates; the other, insoluble in this acid, gave, chromite 0.75, and 43.22 per cent. silicates. A second meteorite, from Cape Girardeau, Missouri, proved, upon examination, to belong to the same general class as the one last mentioned. A catalogue of the meteoric stones in the collection of Yale College, one hundred and forty-seven in number, is published as an appendix in the same number of this journal. Perhaps the most important paper on meteorites which has appeared during the year is that of Reusch. In this are described four Scandinavian meteorites, each of which presents interesting features. The most noteworthy of these is the occurrence of olivine in forms imitative of organic structures, and also, together with bronzite, forming spherulitic bodies in a ground-mass composed of crystals of bronzite, augite, and iron in a glassy base. The most instructive fact in this connection is the discovery of a brecciated structure in two of the meteors described. The rounder grains which occur in the crystalline ground-mass surrounding them are of the same nature as this ground-mass, and are in turn composed of other smaller grains of similar mineralogical composition. A gradual transition from the large fragmental particles to the "chondra" was traced, and from this fact, in connection with the others above mentioned, the author draws certain general conclusions in regard to the origin of meteoric bodies, which, although exceedingly interesting, it would be impossible to incorporate in these notes in any logical sequence. Crystallographic News.-Quite a number of new measurements of crystals have recently been made by Prof. E. S. Dana. GOLD from the White Bull Mine in Oregon possesses the form 303. The crystals are distorted so as to assume a rhombohedral symmetry. Crystals of gold from California showed a persistence of the hexakisoctahedron 180%. THE BROOKITES 3 from Magnet Cove are divided for the sake of convenience into those of prismatic habit and those in which the pyramid is the predominating form. Twenty-five figures of typical crystals are pictured. I Neues Jahrb. f. Min., etc., Beil., Bd. iv., 1886, p. 473. 2 Amer. Jour. Sci., xxxii., Aug. 1886, p. 132. 3 Ib., xxxii., Oct. 1886, p. 314. COLUMBITE.'-A number of new crystals of this mineral from Standish, Maine, have been measured, and from the data thus obtained a recalculation of the axil ratio has been made. According to the new measurements, a : b: c = .40234: : .35798 (Schrauf's position) and .8285: : .88976 (Dana's position). The species is without doubt orthorhombic. Differences in composition appear to have little effect on the value of interfacial angles. DIASPORE.—The two new planes P and P2 were discovered on a fine crystal of diaspore from Chester, Mass. I SULPHUR. P and P are described as new forms on sulphur from Rabbit Hollow, Nev. -Among some remarkably fine crystals of hiddenite, xenotime, monazite, and quartz from North Carolina, Mr. Hidden2. mentions having found on the latter a well-developed basal plane which yielded to Professor Des Cloizeaux, OP / R= 128°, the calculated angle being 128° 13'. On black tourmaline from Sharpe's township, Alexander County, the new form R was detected. On xenotime from the same county 3P was found, and on herderite from Stoneham, Maine, the new plane P. A twinned crystal of molybdenite from Renfrew, Canada, suggests that this mineral may crystallize in the hexagonal system with its planes hemimorphically developed. Amer. Jour. Sci., xxxii., Nov. 1886, p. 386. 2 Ib., xxxii., Sept. 1886, p. 204. (EXTRACTED FROM THE AMERICAN Naturalist, APRIL, 1887.) MINERALOGY AND PETROGRAPHY.' Petrographical News.-The rocks occurring in equatorial Eastern Africa (Massai-Land) have been found by O. Mügge2 to embrace granophyres, gneisses, mica schists, and amphibolites among the older rocks, and liparites, trachytes, nephelinites, nepheline-tephrites and basanites, limburgites, melilitebasalts, augite andesites and feldspathic basalts among the younger ones. The granophyres contain an augite with partings parallel to ∞ P and OP, hypersthene and hornblende, all of which are so closely and peculiarly associated that the author thinks they might be due to the solution in the granophyre substance of some foreign inclusion. The gneisses, schists, and amphibolites also contain a diallagic and an orthorhombic augite. Among the granular constituents of two specimens of amphibolite, prismatic crystals of scapolite were noticed. The porphyritic feldspathic constituent of the trachytes (acmite-trachytes) corresponds very closely to the soda-microcline of Förstner.3 Edited by Dr. W. S. BAYLEY, Madison, Wisconsin. Wollastonite and melanite, which were observed in some of the nephelinites, Mügge thinks must be looked upon as having crystallized directly from the magma of the rock itself, and not as the result of the solution of inclusions. Unfortunately, the author was not able to study these rocks in the field, so that their geological relations are not definitely known.-Bruno Doss has recently made a very thorough investigation of the igneous rocks of Palestine, and as a result of his studies declares them to be labradorite basalts. Their olivine constituent occurs both in porphyritic crystals and in the ground-mass. The two generations are distinguished by the marked differences in their mode of alteration. The mineral of the first generation contains more iron than that of the second, and accordingly gives rise to decomposition products consisting principally of red iron compounds insoluble in acids, while the latter class are merely serpentinized. Twins of olivine were observed in which the twinning planes are P, and in less frequent instances ∞ P. In three specimens pseudobrookite was detected.—The fact that quartz and olivine may occur in the same rock is given additional interest by the discovery in Northern California of a quartz-basalt. This rock is described by Mr. Diller as possessing all the essential characteristics of ordinary basalts, with the addition besides of numerous grains of quartz, many of which are surrounded by a zone of glass and pyroxene. From the fact that quartz is also found in bombs, which must have existed as clots in the lava at the time of its eruption, Mr. Diller is forced to assume that the same magma which under ordinary conditions of temperature and pressure yielded olivine, under different conditions secreted quartz. This quartz-basalt is younger than the ordinary basalts of the region, just as the dacites are younger than the andesites. -The origin of lithophysæ in the acid lavas of the Yellowstone National Park is the subject of a paper by Mr. Iddings 3 in a late number of the American Journal of Science. In it the author inclines to the theory first proposed by Von Richthofen, viz., that this structure is of aqueo-igneous origin, and was produced by the action of absorbed gases upon the molten glass, from which they were liberated during the crystallization consequent, upon cooling. Mr. Iddings is led to this view by the facts (1) that the minerals found upon the walls of the lithophysæ (quartz, tridymite, and fayalite) are those which have been produced artificially only by aqueo-igneous methods, and (2) that the chemical composition of the substances of lithophysæ and of spherulites is essentially the same, and therefore the former cannot have been produced by the alteration of the latter.4-Chrustschoff 5 has isolated zircon Min. u. Petrog. Mitth., vii., 1886, p. 461. 2 Amer. Jour. Sci., Jan. 1887, p. 45. 4 Cf. American Naturalist, Notes, Jan. 1887, p. 70. 5 Min. u. Petrog. Mitth., vii., 1886, p. 423. 3 Ib., Jan. 1887, p. 36. |