Reviews 



"The Stability Relations of the Silica Minerals." By Clarence 

 N. Fenner. Am. Jour. Set., Ser. IV, Vol. XXXVI (1913), 

 pp. 331-84, fig. 9. 

 A report of the results of a rigorous study of the various polymor- 

 phous modifications of silica. The work shows conclusively that the 

 relations between quartz, tridymite, and cristobalite are enantiotropic. 

 New determinations of the inversion points, including those between a 

 and /3 phases of quartz, tridymite, and cristobalite, are given. The 

 paper represents by far the most exact work upon the subject to date, 

 and is made especially valuable by carefully constructed diagrams 

 showing the relations between the various phases. 



A. D. B. 



The Mount Grainger Goldjield. By R. Lockhart Jack. Report 

 No. 2, Geol. Surv. of So. Australia. Adelaide, 1913. Pp. 24, 

 figs. 10, pi. I. 

 Describes very briefly the chief structural features of the region and 

 the more important workings. 



A. D. B. 



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