254 Scientific Intelligence. 



various occurrences in the state are described with the aid of 

 maps, sections and illustrations. Then follows a complete petro- 

 graphic study of these rocks accompanied by many analyses. 

 Their modes of alteration and decomposition and their origin are 

 discussed, and this is succeeded by a mineralogical description of 

 the North Carolina corundum together with an account of its 

 technical properties and uses. The authors then describe its 

 modes of occurrence in this region and elsewhere, following this 

 with a statement of its distribution. Next comes a chapter 

 devoted to the alteration of corundum and a study of the minerals 

 associated with it, which contains a large amount of detailed 

 observations upon many species. The work is concluded with an 

 account of the chromite and other economic minerals of the 

 peridotitic rocks of the region. 



While a considerable part of the matter here given has, in 

 more or less condensed form, been previously published else- 

 where, especially in this Journal, the rest of it is new and the 

 whole thus collected forms a most valuable compendium of the 

 peridotitic rocks of the region and their associated minerals. As 

 such it is, not only of local, but of general interest and will prove 

 of service to the mineralogist, the petrographer and the economic 

 geologist. The volume is well printed and illustrated and is a 

 handsome specimen of the bookmaker's art. l. v. p. 



6. Cancrinite- Syenite from Kuolajarvi ; by J. Gr. Sundell. 

 Bull. Comm. Geol. de Finlande, No. 16, 1905, 20 pp.— The author 

 has analyzed this rare and interesting rock type previously 

 described by Ramsay and Nyholrn (Ibid., No. 1, 1895), and the 

 results of the work, which has been carried out in detail with 

 great care, are as follows : 



Si0 2 , A1 2 3> Fe 2 3 , FeO, MgO, CaO, Na 2 0, K 2 0, H 2 0, C0 2 , Ti0 2 



52-25, 20-46, 3-82, 0-68, 0-14, 2-39, 10-05, 6-18, 1-83, 1-69, 0-32 = 100-15 



This includes traces, or minute quantities, of Zr0 2 , NiO, MnO, 

 SrO, BaO, P 2 6 and S0 3 , which total 0-34. The low silica and 

 very high alkalies are notable. The calculation of the mineral 

 composition shows that it contains nearly 27 per cent of cancri- 

 nite. l. v. p, 



7. Opal Pseudomorphs from White Cliffs, New South Wales; 

 by C. Anderson and H. Stanley Jevo'ns. — The authors offer 

 the latest explanation of these interesting pseudomorphs which in 

 recent years have engaged the attention of a number of miner- 

 alogists. They show that the original mineral must have been 

 monoclinic, with a good cleavage perpendicular to the symmetry 

 plane, with certain interfacial angles and characterized by a cer- 

 tain geological mode of occurrence. It could not, therefore, have 

 been either gypsum, sulphur, anhydrite or celestite, and the 

 writers believe that glauberite, the sulphate of soda and lime, 

 most nearly fills the required conditions and was the original 

 mineral. (Records Austr. Mus., vol. vi, Pt. I, pp. 31-37, 1905.) 



l. v. P. 



