calaboose (n.)

1610s, "any thing dug up;" 1650s (adj.) "obtained by digging" (of coal, salt, etc.), from French fossile (16c.), from Latin fossilis "dug up," from fossus, past participle of fodere "to dig," from PIE root *bhedh- "to dig, pierce."

Restricted noun sense of "geological remains of a plant or animal" is from 1736 (the adjective in the sense "pertaining to fossils" is from 1660s); slang meaning "old person" first recorded 1859. Fossil fuel (1833) preserves the earlier, broader sense.

Ikhthes oryktoi "fossil fishes" were known to the Greeks, along with fossil shells on mountaintops and fossil "seaweed" in Sicilian quarries. They sometimes were taken as evidence of changing sea levels.