Fossil Butte National Monument

Wasatch Formation. the red one.


Historic Quarry

Volcanic tuff. compacted ash or tuff layers.


Organic-poor limestone. shallow waters = more oxygenated = quickest organic matter decomposition.

Organic-rich limestome. deep waters = slower organic matter decomposition = accumulation = dark layers.




http://www.nps.gov/fobu/index.htm