1-155-200 - Ann Ronan Picture Library/Heritage-Images

Folding of rock strata, 1671. Diagram from Danish geologist Nicolaus Steno's Prodromus (1671), showing how rock strata can fold and give different formations. The figures read in reverse order from 25 (bottom right) to 20 (top left). Steno was the first to realise that the study of rock strata and fossils could provide a chronological record of geological events.