Shut-in (river)

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Johnson's Shut-ins panorama

A shut-in is an Ozark term for a river that is naturally confined within a deep, narrow channel. The river becomes unnavigable even by canoe due to the rapids and narrow channels produced as the stream encounters a more resistant rock that is more difficult to erode. In the Johnson's Shut-Ins State Park in Missouri, hard rhyolite and a diabase dike divert the stream into many small streamlets following a complex joint system, "shutting" the river.[1]

The term has an origin in Appalachia, where it was used to refer to a narrow river gorge confined by resistant rock layers.[1]

Examples can be found in Johnson's Shut-Ins State Park in Missouri, where the Black River has become confined in a shut-in.[1] More than ninety other "shut–ins" occur within and around the St. Francois Mountains region of southeast Missouri.[1]

In southern Illinois, the Burden Falls Wilderness area includes a narrow canyon below a waterfall that is confined by a resistant sandstone layer. The gorge is referred to as a shut–in, following the Appalachian usage for the term.

See also[edit]

References[edit]

  1. ^ a b c d Beveridge, p.39 - 62
  • Beveridge, T. R., Geologic Wonders and Curiosities of Missouri, Missouri Department of Natural Resources, 2nd ed. 1990, p. 39–62