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in a few discriminating sentences, analyses of many varieties are given and the structures and textures of all are well described. One of the most commendable features of the volume is the use of only the more important rock-names in the body of the text-the less important ones being relegated to a very comprehensive glossary which forms a convenient appendix to the book. In this respect, as in some others, the volume under review is very much more satisfactory to the untechnical reader than the other volumes of similar character that have recently come under our notice.

The work opens with a description of the rock-forming minerals and a discussion of the principles of rock classification. Following this are the descriptions of the rocks. These are divided into Igneous, Aqueous (including Eolian) and Metamorphic rocks. Each class is divided into groups according to chemical composition, and each group is further subdivided according to texture. The classification is an eminently practical one, and at the same time it can give no offense to the micoscopical lithologist.

In the discussion of the rock-types each chapter begins with a list of analyses; this is followed by comments upon them. Then comes a description of varieties, a statement of relationships, a paragraph on geological occurrence, one on alterations and one on distribution. In that portion of the book that deals with the igneous rocks the glasses are first taken up, then the porphyritic varieties and, finally, the granitic ones. The aqueous rocks are grouped as mechanical sediments, limestones, organic remains and precipitates from solution. Of the metamorphic rocks two great classes are recognized, viz., those produced by contact action and those produced by regional metamorphism.

The above outline of the contents of the volume is very brief, but it is sufficiently full to indicate that the author has covered well the field that such a treatise as this one should cover. This book should find a wide sale among engineers as well as among all teachers who introduce into their courses on geology a description of rocks. It is a far more valuable synopsis of the characteristics of rock types to place in the hands of geological students than the synopses contained in the large text books on geology.-W. S. B.

AMERICAN NATURALIST LIST OF RECENT BOOKS

AND PAMPHLETS.

ALLEN, J. A.—On a Collection of Mammals from Arizona and Mexico, made by W. W. Price, with Field Notes by the Collector. Extr. Amer. Mus. Nat. Hist., Vol. VII, 1895. From the author.

ALVORD, H. E.-Statistics of the Dairy. Bull. No. 11, Bureau of Animal Industry, U. S. Dept. Agric., Washington, 1896.

ANDREWS, C. W.-On the Extinct Birds of the Chatham Islands. Extr. Novitales Zoologicae, Vol. III, 1896. From the author.

BAILEY, L. H.-Plant-Breeding. Five Lectures upon the Amelioration of of Domestic Plants. New York and London: Macmillan & Co. From the publishers.

BEECHER, C. E.-Sketch of the Life and Work of James Dwight Dana. Extr. Amer. Geol. Vol. XVII, 1896. From the author.

Bulletins No. 35, 1895 and 36, 1896, Hatch Exper. Station of the Mass. Agric. College.

Circulars 1-15 inclusive, second series, U. S. Dept. Agric. Div. Entomology. Washington, 1891-1896. From the Dept.

Circulars 4, 1895 and 5, 1896, Bureau of Animal Industry. U. S. Dept. Agric. From the Dept.

COPE, E. D.-Primary Factors of Evolution. Chicago, 1896. Open Court Pub. Co.

Cox, U. O.—A Collection of Birds from Mount Orizaba, Mexico. Extr. The Auk, Vol. XII, 1895. From the author.

Contrib. to

CRANER, F.-On the Cranial Characters of the Genus Sebastodes. Biol. from the Hopkins Laboratory, II, Palo Alto, 1895. From the author. DARTON, N. H.-Geology of the Mohawk Valley in Herkimer, Fulton, Montgomery and Saratoga Counties. Part I, Stratigraphy-Preliminary Report on the Geology of Ulster County. Extr. Rept. State Geol. New York for the year

1893. Albany, 1894. From the author.

DE VIS, C. W.-A Review of the Fossil Jaws of the Macropodidae in the Queensland Museum. Extr. Proceeds. Linn. Soc. N. South Wales, Vol. X, Ser. 2, 1894. From the author.

EISEN, G.-Biological Studies on Figs, Caprifigs and Caprification. Extr. Proceeds. Calif. Acad. Sci., Ser. 2, Vol. V, 1896. From the author.

FRAIPONT, J.-Les Cavernes et leurs Habitants. Paris, 1896. From the publishers, J. B. Baillière et Fils.

GILL, T.-Notes on the Synonymy of the Torpedinidae or Narcobatidae.
-Notes on Orectolobus or Crossorhinus, a genus of Sharks.

-Note on the Fishes of the genus Characinus.

-The Nomenclature of Rachicentron or Elacate, a genus of Acanthopterygian Fishes.

-Note on the Nomenclature of the Poecilioid Fishes.

-The Nomenclature of the Fishes of the Caracinoid genus, Tetragonopterus.

Extr. Proceeds U.

-On the Proper Name of the Gunnels or Butter-fishes

S. Natl. Mus., Vol. XVIII, 1895. From the Museum.

-The Families of Symentognathous Fishes and their Nomenclature.
-On the Application of the Name Teuthis to a Genus of Fishes.
-Notes on the Nomenclature of Scymnus or Scymnorhnus, a genus of

Sharks.

-Notes on the Genus Cephaleutherus of Rafinesque, and other Rays with Aberrant Pectoral Fins (Propterygia and Hieroptera).

-Notes on Characinoid Fishes with Ctenoid Scales, with a Description of a New Psectrogaster.

-The Differential Characters of Characinoid and Erythrinoid Fishes. GORDON, C. H.-Buried River Channels in Southeastern Iowa. Extr. Iowa Geol. Surv., Vol. III, Des Moines, 1895.

Guide Zoologique. Communications diverses sur les Pays-bas publicés à l' occasion de 3 ième Congrés International, Leyde, Septembre, 1895.

HAECKEL, E.-Die Cambrische Stammgruppe der Echinodermen. Aus Jenaischen Zeitschr. f. Naturw., XXX, Bd. 1895.

HOLMES, W. H.-Archeological Studies Among the Ancient Cities of Mexico. Field Columbian Mus. Pub., No. 8, Anthropol. Ser., Vol. I, No. 1, Chicago, 1895. From the author.

LORY, P. AND G. SAYN.-Sur la Constitution du Système Crécaceé aux Environs de Chatillon-en-Diois, Grenoble, 1895. From the author.

Maps from the Geological Survey of Canada. Ottawa, 1895.

Nineteenth Annual Report Department of Geology and Natural Resources of Indiana for 1894. Indianapolis, 1894.

OSBORN, HERBERT AND C. W. MALLY.-Entomological Work for 1895. Bull. No. 32, 1896. Iowa Agric. College.

PARVIN, T.-A Physician on Vivisection. Extrs. Ann. Address before the Amer. Acad. Med., Washington, 1891. Cambridge, 1895. From the author. Report of the Commissioner of Education, 1892-93, Vol. 2, Washington, 1895. Report of the United States Commission to the Columbian Historical Exposition at Madrid, 1892-93. With special papers. Washington, 1895. From the Commission.

RIBOT, TH.—The Psychology of Attention. Chicago, 1896. From the Open Court Pub. Co.

SCUDDER, S. H.-Revision of the American Fossil Cockroaches, with Descriptions of New Forms. Bull. U. S. Geol. Surv., No. 124. Washington, 1895.

-Canadian Fossil Insects. Contributions to Canadian Paleontology, Vol. II, pt. 1. Ottawa, 1895. From the Geol. Surv. Canada.

Seventh Annual Report of the Rhode Island Agric. Exper. Station, 1894. Providence, 1895.

SPIVAK, C. D.-Menstruation. Reprint from the Times and Register, 1891. From the author.

STANTON, T. W.-The Fauna of the Knoxville Beds. Bulletin of the U. S. Geol. Surv., No. 113. Washington, 1895.

Tenth and Eleventh Annual Reports, Bureau of Animal Industry, 1893–94. Washington, 1896.

TRAQUAIR, R. H.-The Extinct Vertebrata of the Moray Firth Area. Reprint from J. A. Harvie-Brown and T. E. Buckley's "Vertebrate Fauna of the Moray Basin." Edinburgh, 1896.

WARD, J. H.-Prophets, Saints and Scientists, the Oracles of the Ages. Dover, New Hampshire, 1896. From the author.

WETTSTEIN, R. v.—Monographie der Gattung Euphresia. Arbeiten des botanischen Instituts der k. k. deutschen Universität in Prag, No. IX, Leipzig, 1896. From the author.

WHITEAVES, J. F.-Revision of the Guelph Formation of Ontario, with Descriptions of a Few New Species.

-Systematic List, with References, of the Fossils of the Hudson River or Cincinnati Formation at Stony Mountain, Manitoba. Palaeozoic Fossils, Vol. III, Pt. 2. Ottawa, 1895. From the Geol. Surv. Canada.

WOODWARD, A. S.-Catalogue of the Fossil Fishes in the British Museum. Pt. III, London, 1895. From the British Museum.

General Notes.

MINERALOGY AND CRYSTALLOGRAPHY.1

Etched Figures on Some Minerals.-Traube brings into deserved prominence the value of the method of etching, and gives the results of an extended series of experiments on the etched figures of a number of minerals. He mentions especially those cases in which the etched figures indicate a higher symmetry than that occasionally shown by the geometrical development of the crystal form. He evidently lays more stress on the etched figures of crystals than on the occasional growth of planes corresponding with a lower symmetry. K F and K F, HF are mentioned as giving good results in many cases where the problem is to etch one of the more refractory silicates, and a caution is given that care must be taken in the use of such powerful reagents.

On cuprite etched figures were produced by H,SO,, HCl, HNO, and KOH, dilute HNO, giving the sharpest figures. The etching indicates a holohedral regular symmetry, notwithstanding that Miers has observed faces of the form (986) in a position suggesting gyroidal hemihedrism.

Phosgenite gives sharp figures with hydrochloric, sulphuric, nitric and acetic acids, also with the caustic alkalies, all pointing toward holo

1 Edited by Prof. A. C. Gill, Cornell University, Ithaca, N. Y. 2 Neues Jahrb. B. B. X, pp. 454-469, 1896.

hedral symmetry. The forms developed on some crystals from Monte Poni had suggested trapezohedral hemihedrism in the tetragonal sys

tem.

Wulfenite from several localities has been reported to be hemimorphic, on the strength of the polar development of the crystal form, but neither the etched figures nor the pyroelectric behavior of the crystals bears this out. Both wulfenite and scheelite act alike in these latter respects and appear to be pyramidal hemihedral, without difference in the two directions of the vertical axis.

Chalcolite, disthene, tourmaline, vesuvianite, dioptase, willemite, nepheline, beryl, adularia and some of the triclinic feldspars were also etched, with the result of confirming the higher symmetry in each case where doubt could exist. Nepheline, as already established by Baumhauer, belongs to the pyramidal hexagonal class of Groth (1st hemimorphic tetartohedral division of the hexagonal system, Liebisch).

Pollucite, Mangano-columbite and Microlite from Rumford, Maine. These minerals were discovered in pegmatite associated with quartz, feldspar, muscovite, tourmaline, lepidolite, spodumene, amblygonite, beryl, cassiterite and columbite. They are described by H. W. Foote. The pollucite, though rare, occurs in rather large masses difficultly distinguishable from white quartz. The analysis proves the mineral to be chemically identical with that from Hebron, Maine, and seems to sustain the view of Wells that the formula is H,Cs, Al(SiO,)9.

The Mangano-tantalite is in the form of dark reddish-brown crystals resembling rutile. A qualitative analysis revealed the presence of Mn, Ta and Ni. The specific gravity, 6.44, would indicate that the last two elements are present in about equal proportions. The form differs somewhat from columbite, as shown among other facts adduced, by the axial ratios.

a:b:c=

Columbite. .82851.8898

Mangano-columbite. .83591.8817

Microlite in beautiful honey-yellow crystals 2 mm. in diameter have a specific gravity of 5.17. The prevailing form is the octahedron, modified by the dodecahedron and sometimes by (113).

Epidote and its Optical Properties.-The peculiar appearance of a gray epidote from Huntington, Mass., led to its detailed investigation by Forbes.* The light color is evidently due to the low percent3 Am. Jour. Sci., CLI, pp. 457-461, June, 1896.

Am. Jour. Sci., CLI, pp. 26--30, 1896.

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