Bonneterre Formation
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The Bonneterre Formation is an Upper Cambrian geologic formation which outcrops in the St. Francois Mountains of the Missouri Ozarks. The Bonneterre is a major host rock for the lead ores of the Misso
Galena in Bonneterre Dolomite (Upper Cambrian; Missouri)
St. Francois Mountains
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The St. Francois Mountains in southeast Missouri are a mountain range of Precambrian igneous mountains rising over the Ozark Plateau. This range is one of the oldest exposures of igneous rock in North
A view towards the St. Francois range from Knob Lick Mountain, a granite and rhyolite knob on the edge of the range
Boulders in Elephant Rocks State Park are residual boulders of weathered Graniteville Granite, a pluton formed 1.4 billion years ago in the Proterozoic by the cooling of magma.
Granite from this region was used for cobblestones on the St. Louis wharf and in the piers of the Eads Bridge (background).
Taum Sauk Mountain is the highest point in Missouri.