The Collaborative International Dictionary of English v.0.48:

Geogony \Ge*og"o*ny\, n. [Gr. ge`a, gh^, the earth + ?
   generation, birth, fr. the root of ? to be born: cf. F.
   g['e]ogonie.]
   The branch of science which treats of the formation of the
   earth.
   [1913 Webster]