222 Scientific Intelligence. 



No. 40. Pp. 277, 2 maps, 6 pis., 55 figs. Helsingfors, 1914. — 

 This work covers the results of a detailed geological study of an 

 area in southern Finland about 40 X 20 miles in area. It consists 

 of a complex of gneisses, called leptites, with some limestones 

 intruded by bodies of granite, diorite, gabbro, and peridotite, 

 also amphibolites of igneous origin. The different varieties of 

 these rocks have been carefully mapped, studied in thin section, 

 and chemically analyzed. One of the granite masses has pro- 

 duced a more or less extensive contact zone in the older leptites, 

 amphibolites, and lime-carbonate rocks with production of a 

 varied group of gneisses carrying cordierite, anthophyllite, anda- 

 lusite, etc., cummingtonite-amphibolite and a lime series with 

 tremolite, pyroxene, and andradite. The region has some eco- 

 nomic interest from the occurrence of sulphide ores and bodies of 

 iron oxides, which have not been much developed. The author 

 states as his conclusion that the characters of the contact rocks 

 are mostly due to pneumatolytic agencies which have brought 

 about a metasomatic replacement of lime, soda, and potash by 

 iron oxides and magnesia. This peculiarity holds without regard 

 to the original nature of the intruded rocks. The ores are 

 thought to have been formed in the same way and at this time. 

 This is an accurate, thoughtful piece of work, of more than local 

 interest, whose perusal will especially repay those engaged in the 

 deciphering of metamorphic-igneous complexes. l. v. p. 



4. The Crowsnest Volcanics, by J. D. MacKenzie. Mus. 

 Bull. No. 4, Geol. Series No. 20, Geol. Surv. Dep't. Mines, Ottawa, 

 1914, pp. 33 ; PI. I. — The occurrence of alkalic rocks described in 

 this paper has been previously mentioned by C. W. Knight in the 

 Canadian Record of Science (vol. ix, p. 265, 1905) as occurring in 

 the southwest corner of Alberta ; he showed that in considerable 

 part the volcanic ejections consisted of analcite, often occurring 

 in crystals of considerable size, and held to be of primary origin. 

 The author has investigated and mapped the areal extent of these 

 rocks, which originally covered a probable field of some 50 by 15 

 miles with a maximum thickness of about 1000 feet. They are 

 thought to have fallen mostly in shallow water toward the end 

 of the Dakota. No definite vents have been found. The rock- 

 types are trachytes, latite, and the analcite-bearing rock which 

 Knight has termed blairmorite, from the adjacent town of Blair- 

 more. The blairmorite, of which several varieties occur, is found 

 as bowlders, often of considerable size, in the water-laid breccias. 

 The most interesting variety consists of a porphyry in which the 

 phenocrysts are well-crystallized analcites an inch in diameter 

 and of a red color, and an equal volume of dark green ground- 

 mass. Occasional phenocrysts of glassy sanidine and small 

 melanites were observed. The groundmass was determined 

 microscopically to consist of 50 per cent analcite with aBgirite, 

 augite, and unaltered nephelite and sanidine. 



By measurements and by specific gravity determinations the 

 mineral proportions of the rock were found to be: 



