490 PETROLOGICAL ABSTRACTS AND REVIEWS 



rock are altered, the character of the resultant depending upon the nature of 

 the country rock. Against sandstone and arkoses there is a decrease in the 

 feldspathoids and a transition to syenite and even to quartz-bearing and 

 nephelite-free alkali granites. Where the igneous rock is in contact with the 

 dolomitic Cambrian rocks there is an increase in the amount of nephelite and 

 the grain is coarse, in some cases giving nephelite-syenite-pegmatite phases 

 with nephelites several centimeters in size. Such changes in the character of 

 the rock cannot be explained by differentiation alone. Kaiser thinks that 

 assimilation of the country rock is clearly indicated, although he supposes that 

 there was also subsequent differentiation. He warns, however, against using 

 such local occurrences either for or against the assimilation theory of magmas 

 in general. The mechanics of the intrusion, he thinks, agree with Daly's 

 theory of magmatic stoping. He believes the magma reached its present 

 position not by intrusion between strata, but by forming a place for itself. 



Kaiser, Erich. "Bericht iiber geologische Studien wahrend des 

 Krieges in Siidwestafrika," Abhandl. d. Giessener Hochschul- 

 geselL, II (1920). Pp. 57, pis. 6, figs. 4 

 A general geological description of Namib, an interesting petrographic des- 

 cription of which is given in greater detail in the preceding paper. The scope 

 of the work is indicated in the chapter headings, some of which are crystalline 

 schists, Cambrian, eruptive rocks, Tertiary, alteration of the Tertiary land 

 surface, underground water, mineral occiirrences, etc. 



Kato, Takeo. "Microscopic Secondary Sulphide Enrichment in 

 the 'Kuromono' Ore from the Kosaka Mine, in the Province 

 of Rikuchii, Japan, Jour. Geol. Soc. Tokyo, XXV (1918), 1-7, 

 pis. I. 



Kato, Takeo. "A Contribution to the Knowledge of the Meso- 

 zoic Igneous Rocks Developed Around the Tsushima Basin, 

 Japan, Jour. Geol. Soc. Tokyo, XXVII (1920), 1-22, 23-38, 

 pis. 4, figs. 2. 

 A porphjnrite complex with associated tuff beds, late Jurassic in age, was 

 invaded by a series of igneous rocks in the following order: (i) effusive quartz- 

 porphyry; (2) intrusive quartz-masanite, masano-tonalite, etc., with melano- 

 cratic marginal fades; (3) tsingtauites and masano-tsingtauites; (4) dikes of 

 masano-hornblendite; (5) aplitic and pegmatitic rocks. The rocks of (i) and 

 (2) were probably derived from the same magma basin; (2), (3), (4), and (5) 

 are clearly related. Sporadic corroded quartz crystals in some portions of the 



