Saint Anthony Falls EarthCache
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Geologists say that the falls first appeared roughly 10,000 years ago several miles downstream at the confluence of the glacial River Warren (at present-day Ft. Snelling). Estimates are that the falls were about 180 feet (55 m) high when the River Warren Falls receded past the confluence of the Mississippi River and the glacial River Warren. Over the succeeding 10,000 years, the falls moved upstream to its present location, breaking off the limestone cap in chunks as it receded. Tributaries such as Minnehaha Creek begot their own waterfalls as the Mississippi River valley was cut into the landscape.
From its origins near Fort Snelling, St. Anthony Falls relocated upstream at a rate of about 4 feet (1.2 m) per year until it reached its present location in the early 1800s. When Father Louis Hennepin documented the falls he estimated the falls' height to be 50 or 60 feet (18 m). Later explorers described it as being in the range of 16 to 20 feet (6.1 m) high. The discrepancy may have been due to scope, as the current total drop in river level over the series of dams is 76 ft (23 m).
The geological formation of the area consisted of a hard, thin layer of Platteville Formation, a carbonate rock, overlaying the soft St. Peter Sandstone sub-surface. These layers were the result of an Ordovician Period sea which covered east-central Minnesota 500 million years ago. The water churning at the bottom of the falls ate away at the sandstone, and after enough support had been removed, large blocks of the Platteville Formation would fall off. This process had been happening naturally since 8000 BC, with the falls having receded up from the Fort Snelling area to their location in the 1850s.
Before European exploration, the falls held cultural and political significance for native tribes who frequented the area. The falls was an important and sacred site to the Mdewakanton Dakota and they called the Mississippi River, hahawakpa, "river of the falls." The falls (haha) themselves were given specific names, mnirara "curling waters," owahmenah "falling waters," or owamni, "whirlpool" (mniyomni in the Eastern Dakota dialect and owamniyomni in the Teton Dakota (Lakota) dialect. Dakota associated the falls with legends and spirits, including Oanktehi, god of waters and evil, who lived beneath the falling water. The sacred falls also enters into their oral tradition by a story of a warrior's first wife who killed herself and their two children in anguish and forlorn love for the husband who had assumed a second wife. The rocky islet where the woman had pointed her canoe towards doom thus was named Spirit Island which was once a nesting ground for eagles that fed on fish below the falls. Dakota also camped on Nicollet Island upstream of the falls and to tap the sugar maple trees.
Since the cataract had to be portaged, the area became one of the natural resting and trade points along the Mississippi between Dakota and Anishinaabe peoples. The Anishinaabe (Ojibwe) term was recorded as "kakabikah" (gakaabikaa, "split rock" or more descriptively, gitchi gakaabikaa, "the great severed rock" which referenced the jagged chunks of limestone constantly eroding by the falls).
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