The First-Ever Geologic Map of a Nation Was Just Rediscovered in London

There's a good chance your last encounter with a geologic map was in 8th grade science class, and your memories of it are sandwiched between awful puns about minerals (I'm not gneiss, I'm full of schist).

But you should care about geologic maps, because they aren't merely arcane tools for those who study earth sciences. They're essential to anyone who uses the earth's resources or builds on it. By visualizing the age, makeup, and relationships of rocks along a given swathe of the earth’s surface, geologic maps are the best, simplest way decision-makers can "identify and protect valuable resources, avoid risks from natural hazards, and make wise use of our land," according to the Idaho Geological Survey. They are the reason your house isn't perched atop an ancient landslide area, and the reason Halliburton fracks where it fracks.