Reviews — United States Geological Survey. 321 



of 250 feet. It is based on the map published in 1904, and gives the 

 relations of the Nelson batholith (granites, monzoiiites, and quartz- 

 diorites) and its accompanying dykes to the rocks of the B.ossland and 

 Pend d'Oreille groups (? Carboniferous). 



X. — Professor Doelter's Mineralogy. 



THE first part of a second volume of Professor Doelter's great 

 work (Mandbuch der Miner alchemie, edited by Hofrat Professor 

 Dr. C. Doelter ; vol. ii, pt. i, pp. 160; Dresden and Leipzig, 

 Theodor Steinkopff, 1912; price 6-50 marks net), which deals with 

 silica and the silicates, comes fully up to its predecessors in point 

 of view of interest and importance. It opens with a resume by 

 Professor Becke of the physical characters of the silicates. He 

 compares the refraction of many species with the corresponding 

 value calculated from Gladstone and Dale's well-known law ; the 

 agreement is often very close, but discrepancies are met with which 

 call for farther investigation. The general theory of the optical 

 characters of isomorphous mixtures is considered, with special 

 reference to the plagioclase felspars. A lucid and thorough account 

 of the paragenesis of the silica minerals comes from the pen of 

 Professor J. Koenigsberger. Professor Doelter himself writes on the 

 vexed question of the constitution of the silicates, and discusses 

 the various theories that have been put forward. He also describes 

 very fully the physical characters of quartz, chalcedony, and opal, 

 the information given being exhaustive and well up-to-date. 



XI. — United States Geological Survey. 



WE have received Water-supply Papers Nos. 281, 283, and 301, 

 ■ dealing with the Surface Water Supply of the United States, 

 including the North Atlantic Coast and Ohio River Basin ; also 

 No. 299, part ii, dealing with stream measurements in San Joaquin 

 Eiver Basin, California. Illustrations are given of the apparatus 

 used in gauging the flow of streams. In No. 299 there are views 

 showing the measurements made by the engineers of the Geological 

 Survey by means of a current meter, which is operated from a bridge, 

 a car suspended on a cable, a boat, and by wading. 



The Thirty-third Annual Report of the Director (Mr. George Otis 

 Smith) for the year ended June 30, 1912, contains a useful map 

 showing areas of the United States covered by geologic surveys. 

 There are some interesting remarks on the work of the Committee on 

 Geological Names, their duty being to consider all geologic names 

 of formations suggested by members of the Survey, prior to 

 publication in both official and unofficial works. During the past 

 fiscal year the Committee " considered 143 manuscripts, comprising 

 a total of 21,614 pages and about 5,000 geologic names". Various 

 card-catalogues bearing on nomenclature are kept up for the 

 Committee, whose useful labours might well be followed in other 

 countries. 



decade v. — VOL. X. — NO. VII. 21 



