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Boulder Flatirons
Hart Van Denburg/CPR News
Hikers in a meadow below the Flatirons in Boulder, Colorado, Monday April 15, 2019.

Ancestral Rockies

Before the Rocky Mountains rose from an ancient ocean, and before that ancient ocean submerged Colorado under water, there were other mountains here: The Ancestral Rocky Mountains. 300 million years ago, with the force of colliding continents driving them upward, these Rockies rose to heights unknown. But then time and erosion wore down those Ancestral peaks, grain by grain, until they became the floor of a great interior seaway. The mountains were gone for good, or seemed to be, until another great uplift for a new generation of Rocky Mountains tilted that long calcified seabed upward with it, bringing a trace of the Ancestors: the Flatirons, Red Rocks, the Maroon Bells. Ancient evidence of an unknowable mountainous majesty, in a prehistoric Colorado.

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About Colorado Postcards

Colorado Postcards are snapshots of our colorful state in sound. They give brief insights into our people and places, our flora and fauna, and our past and present, from every corner of Colorado. See more postcards.


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The Denver Mint

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Hard-rock mining brought a workforce to Colorado in the 1800s. Successful operations, like the Smuggler Mine near Aspen, had hundreds working two or three shifts a day.