Geology and Mineralogy. 311 



A. trilobitus. He observes that the Brachypyge Carbonis de- 

 scribed by Woodward as the abdomen of one of the Brachyui-an 

 Crustacea is probably the abdomen of an Anthracomartus. 



5. Revision of the Palwocrinoidea by C. Wachsmuth and F. 

 Springer. — Part III of this important memoir published in the 

 Proceedings of the Academy of Natural Sciences, has been com- 

 pleted. It covers 138 pp. 8vo, and is illustrated by plates IV to 

 IX inclusive. 



6. Geology — Chemical, Physical and Stratigraphical ; by 

 Joseph Prestwich, M. A., F.R.S., F.G.S., Prof. GeoL Univ. Oxford. 

 In two volumes : V 'ol. I, Chemical and Physical Geology. 477 pp. 

 8vo. — Professor Prestwich's long labors in geology have sup- 

 plied him with much material of his own observation for his 

 geological treatise, and have enabled him to prepare a work that 

 will contribute largely to the progress of the science. The volume 

 now issued, after an introductory chapter, takes up the subject 

 of the constituents of the' earth's crust — its rocks. A review 

 of the animal and vegetable kingdoms follows. Afterward the 

 work treats of the formation of sedimentary deposits and the 

 atmospheric and other agencies concerned, of ice-action, volcanoes, 

 earthquakes, and coral islands. Then follow chapters on the 

 disturbances of rocks with their effects, on mountain-ranges, on 

 metalliferous deposits and veins, on igneous rocks and metamor- 

 phism. The various principles of the science are explained 

 through well-selected facts and illustrated by numerous excellent 

 figures, many of which are new to text-books. Among the latter, 

 the one of the interior of Kilauea, we should like to modify. 

 Besides figures in the text, there are also folded plates of sections, 

 and three folded maps of the world, which add much to the value 

 of the work. Of the latter, one is a colored map of the geological 

 formations ; another, colored, shows the oceanic currents and the 

 distribution of coral reefs and islands ; the third gives the distri- 

 bution of volcanoes. The volume is from the Clarendon Press, 

 Oxford. 



7. Artificial minerals. — M. A. de Schultejst, who has already 

 accomplished many interesting results in chemical mineralogy, 

 has recently succeeded in forming artificially the hydrous iron 

 phosphate compound, Fe 2 P 2 8 + 4aq, which exists in nature as 

 the mineral strengite ; the rose-colored crystals obtained had a 

 specific gravity of 2*74 and unlike strengite seemed to be mono- 

 clinic in crystallization. The method employed was to heat in a 

 sealed tube, at 180° to 190° C, 26 cc. of a solution of the salt 

 Fe 2 Cl 6 -fl2aq with 4 or 5 cc. of a solution of a specific gravity 

 1-578. 



The same chemist has formed a hydrate of magnesium in small 

 distinct hexagonal crystals (the mineral brucite), and also made a 

 crystallized hydrate of cadmium, in flattened hexagonal prisms, 

 optically uniaxial. 



8. Palaeontology of New York ; by James Hall. Vol. V, 

 Part II, Lamellibranchiata. — The Plates of Vol. V, Part I of 



