William Smith’s Geological Map of England and Wales (1815)
"'The Map that Changed the World': The first nationwide geological strata map"
Self-taught canal surveyor William Smith proved that geological rock layers can be identified and correlated over vast distances by their fossil contents. He hand-painted 15 giant sheets to create the world's first national geological map.
- First systematic use of colored thematic shading to depict underground rock strata
- Darker color shading along the base of each stratum layer showing vertical tilt
- Identified fossil index sequences matching rock ages
Image credit and reuse
William Smith’s Geological Map of England and Wales (1815)
William Smith; via Wikimedia Commons
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The Rhetorical & Ideological Argument
"Beneath the visible surface of property borders and political kingdoms lies a three-dimensional vertical history of the Earth, organized in orderly strata and rich in industrial coal and iron."
- First systematic use of colored thematic shading to depict underground rock strata
- Darker color shading along the base of each stratum layer showing vertical tilt
- Identified fossil index sequences matching rock ages
- Pre-Cambrian metamorphic basement rocks (labeled vaguely as 'Killas')