From Latin strātum 'layer' + Greek -graphia 'description,' the study of rock layers pioneered by canal surveyor William Smith.
The branch of geology concerned with the order and relative position of strata (rock layers) and their relationship to the geological time scale.
From Latin strātum 'something spread or laid down' (past participle of sternere 'to spread') + Greek -graphia 'writing, description.' William Smith, an English canal surveyor, established the principles of stratigraphy in the 1790s by observing that the same fossil sequences appeared in the same rock layers across England. Key roots: *sterh₃- (Proto-Indo-European: "to spread, stretch"), *gerbʰ- (Proto-Indo-European: "to scratch, carve").