The Belknap Mountains are on the southwestern shore of Lake Winnepesaukee, in central New Hampshire. The district of which the geology has been mapped is slightly over one hundred square miles in area and includes adjacent parts of the Winnepesaukee, Gilmanton, Alton, and Wolfeboro topographic sheets.
The Belknap area is of particular interest to the petrographer and structural geologist. The structure is that of a ring-dike complex; and, although similar features have been observed and described elsewhere in New Hampshire, notably in the Ossipee Mountains,1 the Percy area,2 and the Franconia quadrangle,3 many features are better exposed in the Belknap area. The lithologic sequence is more readily determined, and the exposures are better. The rocks are largely igneous; the most unusual are those belonging to the White Mountain (alkaline) magma series,4 which includes gabbro, diorite, monzodiorite, syenite, quartz syenite, . . .