|Name||St. Francois mountains volcanic supergroup|
|Geologic age||Precambrian Y|
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic-ash flow)
Igneous > Volcanic > Felsic-volcanic > Trachyte (Pyroclastic-ash flow)
|Comments||The St. Francois Mountains is a region of formerly extentive volcanic terrane comprising several calderas, cauldron subsidence structures, ring intrusions, and resurgent cauldrons. Three calderas are recognized: the Taum Sauk, the Butler Hill, and the Hawn Peak.|
|Stratigraphic units||Includes Taum Sauk Group and Butler Hill Group.|
Howe, W.B. and Koenig, 1961, The Stratigraphic Succession in Missouri: Missouri Geological Survey and Water Resources, Vol XL. 2nd Series.
|Counties||Carter - Iron - Madison - Reynolds - Saint Francois - Shannon - Washington - Wayne|