St. Croix River flowing through the Dalles of the St. Croix at Interstate State Park in Taylors Falls, Minnesota, USA. (5 June 2015) (downstream is to the right)
The Dalles of the St. Croix is a relatively narrow, rock-lined gorge through which the St. Croix River flows. It is most easily viewed from either the Wisconsin or the Minnesota side of Interstate State Park.
The rocks making up the gorge are 1.1 billion year old flood basalt lava flows (Clam Falls Volcanics) that filled up an ancient rift valley called the Mid-Continent Rift.
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