After the tragic premature death of George Huntington Williams in 1894, the attempt by four young American petrographers to collaborate on construction of a quantitative classification of igneous ...

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THE closing years of the nineteenth century witnessed a revival of interest in the petrology of gneous rocks, which must be regarded as marking an important stage in the development of that subject.

VOLUMES 3 and 4 of this work complete what must be the most compendious hand book of petrography ever issued. In the first volume Johannsen gave an admirably illustrated account of rock textures and ...