Geology and Natural History. 85 



logical conditions ; the propagation of sound waves ; the accumu- 

 lation and transportation of ashes ; the abnormal changes in the 

 height of water at Kagoshima Bay ; also the changes of level and 

 horizontal displacements in the ground. A series of excellent 

 charts illustrate the entire subject, and help to make the volume 

 a notable addition to vulcanology. 



13. Mineraloyic Notes, Series 3 ; by W. T. Schaller, IT. S. 

 Geol. Surv., Bull. 610, 1916 ; pp. 104, 5 pis., 99 figs.— In this report 

 Dr. Schaller gives the results of the various smaller pieces of 

 mineralogical investigations carried on by him in the chemical 

 laboratory of the Geological Survey, between Juty, 1911, and 

 January, 1914. It includes some twenty-five different com- 

 munications, the majority of which have not been completely 

 published elsewhere. Among these are the descriptions of five 

 new species, namelj', koechlinite, inyoite, meyerhofferite, lucinite 

 and velardenite. Important contributions concerning variscite, 

 schneebergite, romeite and the melilite group are included. 

 Through the courtesy of Dr. Schaller it was possible to publish 

 in the Third Appendix to Dana's System of Mineralogy, issued 

 last year, brief summaries of the descriptions of the new species 

 together with the other more important results which are given 

 in this Bulletin. w. e. f. 



14. The Emerald Deposits of Muzo, Colombia ; by J. E. 

 Pogue. Reprint from the Trans. Amer. Inst. Min. Eng., 1916. — 

 This paper gives a brief and interesting account of the history, 

 geology and mineralogy of the famous emerald deposits of 

 Colombia. The emeralds are found almost entirely in calcite 

 veins that traverse a black, carbonaceous, intensely folded forma- 

 tion consisting of thin-bedded shale and limestone. This forma- 

 tion lies discordantly upon steeply dipping strata composed of 

 heavier beds of carbonaceous limestone intercalated with black 

 shale. Between the two formations are thin layers of three other 

 rocks consisting of (1) chiefly albite, (2) a granular aggregate of 

 calcite, dolomite, quartz and pyrite, (3) aggregates of large cal- 

 cite rhombs in a tine-grained matrix. Small amounts of peg- 

 matite have been observed. The presence and association of 

 emerald, parisite, fluorite, apatite, albite and barite in a sedimen- 

 tary formation indicates the action of strong mineralizing 

 solutions which introduced them. Structural conditions indicate 

 that the emerald formation was overthrust to its present position 

 upon the underlying series, and that this movement was followed 

 by a period of mineralization which attained its most conspicuous 

 results along the fault plane and its economic results above that 

 plane. w. e. f. 



15. Microscopical Determination of the Opaque Minerals: 

 An Aid to the Study of Ores ; by Joseph Murdoch. New York, 

 1916, pp. vi, 163 (John AViley and Sons). — Since the publication in 

 1906 of a paper by W. Campbell on " The Microscopical examina- 

 tion of opaque minerals," the use of this new and important 

 means of identification of these minerals has been steadily grow- 



