What is "geognosy"

Geognosy \Ge*og"no*sy\, n. [Gr. ge`a, gh^, the earth + gnw^sis knowing, knowledge, fr. gignw`skein to know: cf. F. g['e]ognosie.] That part of geology which treats of the materials of the earth's structure, and its general exterior and interior constitution.

n. The geological study of the Earth's structure and composition.