Colorado Stromatolite

Description

About 92 million years ago Colorado was under a shallow sea. In that sea, stromatolites formed. Stromatolites are formed by a blue-green bacteria that produce the lime that ultimately makes limestone. Over time these form algal mats, which in turn became the Earth's oldest fossils. In northwestern Colorado, about 70 miles from the Dinosaur National Monument, stromatolites can be found in washes that also contain flint.
Small polished piece. Clearly shows the layers swirled by currents under the crust, and a slice of the crust itself. The piece is 3.57 x 1.3 x 0.85 inches and weighs 2.25 ounces.
ref:10-27