1799, from geology + -ic. Geologic time is attested from 1846.
Entries linking to geologic
geology n.
1795 as "science of the past and present condition of the Earth's crust," from Modern Latin geologia "the study of the earth," from geo- "earth" + logia (see -logy). German Geologie is attested by 1785. In Medieval Latin, geologia (14c.) meant "study of earthly things," i.e. law, as distinguished from arts and sciences, which concern the works of God. Darwin used geologize as a verb.
There rolls the deep where grew the tree.
O earth, what changes hast thou seen!
There where the long street roars, hath been
The stillness of the central sea.
The hills are shadows, and they flow
From form to form, and nothing stands;
They melt like mist, the solid lands,
Like clouds they shape themselves and go.
[from "In Memoriam," 1850]
-ic
Middle English -ik, -ick, word-forming element making adjectives, "having to do with, having the nature of, being, made of, caused by, similar to," from French -ique and directly from Latin -icus or from cognate Greek -ikos "in the manner of; pertaining to." From PIE adjective suffix *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames. In chemistry, indicating a higher valence than names in -ous (first in benzoic, 1791).
In Middle English and after often spelled -ick, -ike, -ique. Variant forms in -ick (critick, ethick) were common in early Modern English and survived in English dictionaries into early 19c. This spelling was supported by Johnson but opposed by Webster, who prevailed.