The US Geological Survey has published the Geologic Map of the Denver West 30′ x 60′ Quadrangle, North-Central Colorado. A picture may be worth a thousand words, but a good geologic map can be worth a thousand pictures. The geological story told by this map portrays 1.79 billion years of sedimentation, igneous activity, metamorphism, deformation, and erosion.
Plus, a good geologic map is a work of art:
Grace and Peace