328 Reviews — BritisJi and Foreign Marbles. 



bituminous coals, which often contain as much as 23 per cent of 

 moisture. Among the rocks there is a curious series of dyke or vein 

 rocks of unknown origin called "haematite quartz rocks", which 

 are placed in a class by themselves. They consist principally of 

 haematite and chalcedony, and have an iron content of 47 to 54 per 

 cent of Fe 2 0"3, which occasionally rises as high as 92 per cent in 

 the haematite rocks. In the section on meteorites twelve undoubted 

 siderites of nickeliferous iron are described, the large numbers of 

 doubtful obsidianites which have been found in the colony being 

 neglected. The natural waters analysed are drawn from a variety 

 of sources — artesian wells, surface wells, and mines. They are 

 used for drinking water, steam-raising, irrigation, stamp batteries, 

 and the cyanide process. The amount of solid matter is often very 

 high, sometimes reaching more than 15 per cent, which is principally 

 sodium chloride. It is interesting to note that in the surface waters 

 of one district there is a considerable quantity of sodium nitrate, 

 amounting to 19 parts of nitrogen to the million. This is attributed 

 to a train of favourable circumstances, there being great bacterial 

 activity in the soil, low rainfall, and a dominant vegetation of 

 a leguminous plant called " mulga". 



"W. H. Wilcockson. 



III. — British and Foreign Marbles and other Ornamental Stones. 



By John Watson. Cambridge University Press, 1916. 5s.net. 

 flMIIIS descriptive catalogue is a companion volume to the same 

 i_ author's well-known Building Stones, and it shows the same 

 scholarship and regard for accuracy that characterized the earlier 

 catalogue. The rocks described include (besides marbles) onyx 

 marbles, malachite, alabaster, serpentine, and jade, as well as other less 

 common ornamental stones. The work will appeal very strongly to 

 the architect, and to the geologist who is interested in the application 

 of rocks to decorative purposes. 



IV. — The Etchegoin Pliocene of Middle California. By Jorgen 0. 



Nomland. University of California Publications, Bulletin of the 



Department of Geology, vol. x, No. 14, pp. 191-254, pis. vi-xii, 



2 text-figures. Issued April 19, 1917. 



f PHIS memoir treats very exhaustively of the Etchegoin group of 



1_ rocks and its fauna as developed in the Coaliuga District of 



Middle California, which is considered to be of Pliocene age, although 



mapped as Upper Miocene by Ralph Arnold and F. M. Anderson. 



The author regards the vertebrate evidence as confirmation of this 



horizon, Professor J. C. Merriam having recently described from 



these beds such genera as Plioliippus, Neohipp avion, Mastodon, etc. 



Faunal lists are drawn up of the marine invertebrates showing 



a strong resemblance to those of the Jacalitos formation, which, 



although hitherto kept distinct, may now, in the author's opinion, 



be united to the Etchegoin group. The memoir terminates with 



descriptions of several new species of Mpllusca — seven Pelecypoda 



and 8 Gasteropoda — and a doubtful Serpida, all of which are suitably 



figured. 



