Title: Precambrian geology, Gravenhurst area / by S.B. Lumbers, V.M. Vertolli and W.M. Schwerdtner
Subjects: Geology -  Ontario - Muskoka Township, Geology - Ontario - Morrison Township, Geology - Ontario - Longford Township (west), Geology - Ontario - Gravenhurst area, Geology - Ontario - Ryde Township, Geology  - Ontario - Draper Township, Geology - Ontario - Dalton Township