Reviews — Brief Notices. 179 



suggests a grouping based upon a genetic geological basis, as 

 follows : I. Endogenetic deposits : (1) igneous segregations, 

 (2) igneous exudations, (3) deposits in thermo-dynamically altered 

 rocks (unfused and unimpregnated). IE. Exogenetic deposits: 

 (1) weathering residues, (2) detrital deposits, (3) solution deposits, 

 (4) subaerial plant accumulations and their products. 



Many famous mineral localities are incidentally described in this 

 volume : among them may be mentioned the gold-telluride mines in 

 Western Australia and Colorado, the quicksilver mines at Almaden, 

 the Broken Hill silver dead mines, the Burra Burra copper mines, the 

 famous Swedish iron deposits, the pyrites deposits at Bio Tinto, the 

 Saxon-Bohemian Erzgebirge, the Straits Settlements tin deposits, 

 and the Cornish mines. 



The volume is admirably illustrated and provided with excellent 

 subject and geographical indices, and is altogether one that should 

 find a welcome home on the shelves of all who are interested in either 

 rocks in general or ore-deposits in particular. 



IV. — Brief Notices. 

 1. The Production of Mineral Waters in 1913 ; with a Discussion 

 of their Radio-activity - . By R. B. Dole. Mineral Resources of 

 the United States, calendar year 1913. Part II. pp. 393-440. 

 1914. 

 TPHIS report contains statistics of the natural mineral waters of the 

 1 United States, arranged according to States. It includes two 

 features of interest : a bibliography of mineral water analyses, and 

 a short account of the radio-activity of mineral waters. Many mineral 

 waters do not differ in any obvious way from ordinary town supplies 

 in their composition. Yet such waters have a distinct therapeutic 

 value, and in recent years the previously obscure curative agent has 

 been identified with radio-active ingredients which the medicinal 

 waters have been found to contain. A table showing the radio- 

 activity of about fifty well-known waters is given, but unfortunately 

 the radio-activity is expressed according to five different units, and 

 direct comparison is thus impeded. A bibliography is provided of 

 literature bearing on radio-activity and radio-therapy, and is a useful 

 compilation ; but one notices the rather serious omission of Sir E. 

 Rutherford's Radio-active Substances, 1913, which should have taken 

 the place of his 1906 book. 



2. Portuguese East Africa. — Messrs. E. 0. Thiele and R. C. Wilson 

 publish in the Geographical Journal for January, 1915, a tectonic and 

 physiographic account of the area between the Zambesi and Sabi 

 Rivers. But in the discussion, which followed, are some remarks by 

 Mr. R. B. Newton on important fossils collected, and these remarks 

 are liable to be overlooked. The collection' is now in the British 

 Museum, and belong to Upper Cretaceous, Lower Eocene, and Miocene 

 times. The latter is recognized for the first time from the presence 

 of the foraminiferal genus Amphistegina ; whereas the Eocene was 

 identified from Nummulites as far back as 1896 (Geol. Mag., 1896, 

 487) from material collected by David Draper about 100 miles south 

 of the area whence Mr. Thiele obtained his specimens. 



