Webster's Revised Unabridged Dictionary · 1913

Geology

Geology , noun

[Greek ge`a, gh^, the earth + -logy: compare French géologie.]

1.
The science which treats: (a) Of the structure and mineral constitution of the globe; structural geology. (b) Of its history as regards rocks, minerals, rivers, valleys, mountains, climates, life, etc.; historical geology. (c) Of the causes and methods by which its structure, features, changes, and conditions have been produced; dynamical geology. See Chart of The Geological Series.
2.
A treatise on the science.