This paper is a summary of the petrography and petrology of the largest granite batholith in Minnesota. The granite is of Algomian age and reached its position partly by crowding out its walls and largely by stoping upward into mica schists. Its main phase is a fresh biotite granite of no great peculiarity. Its minor phases, modified by metamorphism or assimilation, are of little importance. A series of satellitic stocks are notably alkalic. Along the edges of the granite there are considerable masses and an interrupted belt of darker, usually hopblendic rock. In places this has differentiated into banded rocks of considerable variety, syenites, shonkinites, pyroxenites, and even magnetite rock. This series is not common in granite batholiths. It probably indicates the general course of evolution in the pre-Cambrian batholiths of the Canadian shield, few of which have been studied in detail. Several new analyses of special phases are given, and it is suggested that they separated by crystallization during...