Reviews — Faunas of North America. 39 



commercial application of minerals, and contains much valuable 

 information on the mode of occurrence, the treatment of the ores, 

 and the uses to which the products are put. Statistics are given of 

 the production of the various minerals and the exports and imports 

 in the case of the United States, and often the figures for other 

 countries are added. 



In the chapter on Bauxite and Aluminium the Serpek process for 

 fixing nitrogen by means of bauxite is described. The reaction is of 

 the type Al 2 3 + 3 C + 2 N = 2 Al N + 3 C 0, the aluminium nitride 

 yielding with water ammonia and alumina, the latter in a very pure 

 form. In another chapter an alloy of nickel, chromium, and copper 

 is described which withstands the solvent action of strong acids. 

 The chapter on the recovery of secondary metals reveals the 

 remarkable dimensions which the treatment of scrap metal has 

 reached, nearly seventy-three million dollars worth of metal being 

 recovered in the United States, and that exclusive of gold, silver, 

 platinum, and iron. A new mica product, which has been put on 

 the market under the name ' micarta ' by the Westinghouse Electrical 

 and Manufacturing Company, is a tan-coloured, hard, and homo- 

 geneous material which can be sawn, milled, and threaded, and does 

 not warp to any appreciable extent. One grade of it, ' bakelite 

 micarta,' is infusible, and insoluble in nearly all the ordinary 

 solvents. We notice on turning over the pages what a large variety 

 of minerals are used in the decorative arts, the textile industry, and 

 paper manufacture. 



IV. — Middle Triassic Marine Invertebrate Faunas of North 

 America. By J. Perrin Smith. Professional Paper No. 83 of 

 the United States Geological Survey. 4to ; pp. 148 and 99 

 plates. 1914. 



R. J. PERRIN SMITH'S memoir on the above is a handsome 

 and well-illustrated survey of three orders of Cephalopoda 

 (Ammonoidea, Belemnoidea, and Nautiloidea) and some genera of 

 Lamellibranchia, Brachiopoda, and Crinoidea. The work forms the 

 second part of a series of three volumes on the marine invertebrate 

 faunas of the Lower, Middle, and Upper Trias of North America 

 which continues and supplements a previously published work by 

 the same author, consisting of a synoptical introduction to the whole 

 fauna. Professor Alpheus Hyatt and Mr. Smith originally proposed 

 to produce a joint monograph on this subject, but owing to Professor 

 Hyatt's advanced age the project was not proceeded with, and 

 ultimately Mr. Smith's introduction, in the preparation of which 

 he had Professor Hyatt's assistance, was substituted, appearing as 

 Professional Paper No. 40 of the Survey. 



The present work will be mainly interesting to the general student 

 (apart from the specialist) for its excellent summary of the relationship 

 of the fauna of the Middle Triassic seas of North America to those of 

 the Eastern Hemisphere. Mr. Smith's conclusion on this question is 

 that the kinship between the American and Mediterranean faunas 

 is closer than that between the American and Asiatic. In addition 



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