Geology and Mineralogy. 159 



6. Invertebrates from the Eocene of Mississippi and Alabama; 

 by Otto Meyer, M.D. 6 pp. with one plate. (Proc. Acad. 

 Nat. Sci., Phila., 188V). — Mr. Otto Meyer describes in this paper 

 a number of new species of fossils found by himself, and gives 

 good figures of them on the accompanying plate ; and notes are 

 added with figures also of some insufficiently known species. 



1. Contributions to Mineralogy ; by F. A. Genth. — Dr. Genth 

 has added another to his series of important papers upon Ameri- 

 can minerals. This contains a number of analyses of cassiterite 

 and of tin ores from Zacatecas, Mexico ; they are interesting as 

 showing the presence of a large amount of foreign matter chiefly 

 As o 6 , Fe 2 3 in the specimens of tin stone. A description is also 

 given of the mimetite associated with the tin ore from the Mina 

 del Diablo; it appears in pseudomorphous forms, well shown in a 

 phototype plate, these in part resemble reticulated galena but 

 are not all reconcilable with an original isometric form. Dr. 

 Genth suggests that the original mineral may have been anglesite 

 with which the measured angles agree pretty well. Two analyses 

 (by H. F. Keller) are given of samples of vanadinite associated 

 with descloizite from the Mammoth Gold Mine near Oracle, 

 Pinal County, Arizona, and another by the author from Yavapai 

 County. 



The peculiar variety of descloizite from San Luis Potosi, called 

 cupro-descloizite by Rammelsberg, ramirite by Velasquez, is 

 analyzed anew with results identical with those of Penfield (this 

 Journal, xxvi, 361) ; the remark is made that the tritochorite 

 of Frenzel may probably have been the same mineral. Analyses 

 are also given of hessite from Arizona, allanite from Chester 

 County, Penn., and hisingerite from the Ducktown Mines, Ten- 

 nessee. 



8. Silver in volcanic Ash. — Professor Mallet has analyzed a 

 specimen of volcanic ash collected on the Pacific coast in Ecuador, 

 120 miles west of Cotopaxi. The ash fell on July 23, 1885, and 

 formed a deposit to the depth of several inches. The interesting 

 feature in the composition of the material was the presence of a 

 small amount of silver, probably as silver chloride ; several 

 experiments showed that silver was present to the extent of 1 

 part in 83,600 of ash. This is the first time that silver has been 

 identified in material ejected from a volcano. — Proc. Roy. Soc, 

 xlii. 



9. Sixth Annual Report of the State Mineralogist of Cali- 

 fornia. Part I, 145 pp. 8vo. Henry G. Hanks, State Minera- 

 logist; Part 11,222 pp. William Irelan, Jr., State Mineralo- 

 gist. — These two parts are published separately and bear the dates 

 of 1886, 1887 respectively. The first, by Mr. Hanks contains 

 chapters on the building stones of California, the mineral springs, 

 a table of altitudes, and finally a check list of California minerals. 

 Part II by Mr. Irelan is largely devoted to the gold mines of the 

 State with descriptions of methods of working, a summary of the 

 U. S. Mining Laws, etc. 



