Laramie Formation
Laramie Formation outcrops on Jolly Ranch

The Laramie Formation is famous for its coal beds. The lower 100 feet of this 300-foot-thick formation commonly contain 5–10 beds of coal, each of which may be seven feet thick. We pass by them unknowingly today, but a hundred years ago residents of the Denver Basin were keenly aware of where their fuel came from. Homes were heated and trains run on coal mined from the Laramie Formation near Denver.

Finding the Laramie Formation is difficult; you can only see it in a few places near Denver. Look for dark streaks of carbon-rich shale. These rocks give you a sense of an oozy landscape that existed behind the retreating Interior Seaway. This formation includes deposits that accumulated near sea level overlain by sediments from slightly higher, better-drained topographic settings.

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