336 Revieivs — Mineral Resources of Great Britain. 



derived from a highly alkaline syenitic magma. Manganese is now the 

 most important of the mineral products of Brazil, and in 1916 the 

 production was nearly half a million tons, mostly shipped to the 

 United States, replacing supplies formerly obtained from India 

 and Russia. 



It is impossible in the space at our disposal to mention even a 

 tithe of the interesting facts connected with the mineral wealth of 

 South America, both developed and undeveloped ; we can only 

 advise all geologists who feel any interest in the economic side of 

 their subject to read this book, which is indispensable to the practical 

 man, and contains a mine of information of value to those dealing 

 with the geology of all mineral products, metalliferous and non- 

 metalliferous, salts, coal, oil, and gems. 



R, H. Rastall, 



Special Reports on the Mineral Resources of Great Britain. 

 Vol VI : Refractory Materials. 2nd edition. Mem. Geol. 

 Survey, pp. vi -f- 241, with 3 plates and 8 text-figures. 1920. 

 Price 7s. 6rf. net. 



rpHE first edition of this memoir, published in 1917, was reviewed 

 -■- at some length in this Magazine, and this edition does not show 

 many changes ; a few small corrections have been made, but in the 

 main the descriptions remain as before ; the field-staff has been 

 engaged on other work, and no re-examination of the mines and 

 quarries was found possible. We trust that this does not mean that 

 the volumes of this most useful series will not be kept up to date 

 by frequent revision, as has been anticipated. It is, however, 

 satisfactory to find that another volume is in the press giving the 

 chemical analyses, petrological description, and results of refractory 

 "tests of the materials here described. This will add much to the value 

 of the present work. 



Earthquakes in Oregon. By Warren Dupre Smith. Bulletin 

 of the Seismological Society of America, vol. ix, 1919, pp. 59-71. 



nnHOUGH sometimes supposed to be immune from earthquakes, 

 -*- the State of Oregon, as this short paper shows, has been 

 disturbed by thirty earthquakes during about the last seventy years, 

 most of them slight, but among them were two strong enough to 

 damage buildings. The records are, however, too scanty to lead 

 to results of much scientific value. 



C. D. 



