2018 Hardrock 100 – The Great Uncomfortmity Published on August 7, 2018 in Eyes Wide Open: A Runner’s View of the 2018 Hardrock 100 CourseFull resolution (1800 × 1350) < Previous Next > I stop whenever I pass the textbook Great Unconformity in Box Canyon, where a whooping 1.3 billion years of geology is missing between the 1.4-billion-year-old bottom Precambrian rock at the roughly 27-million-year-old volcanic San Juan Tuff above.
