The River Warren Falls was a massive waterfall on the

glacial River Warren Glacial River Warren, also known as River Warren, was a prehistoric river that drained Lake Agassiz in central North America between about 13,500 and 10,650 BP calibrated (11,700 and 9,400 14C uncalibrated) years ago. A part of the uppermost porti ...

initially located in present-day

Saint Paul, Minnesota Saint Paul (abbreviated St. Paul) is the List of capitals in the United States, capital of the U.S. state of Minnesota and the county seat of Ramsey County, Minnesota, Ramsey County. Situated on high bluffs overlooking a bend in the Mississip ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. The waterfall was 2700 feet (823 m) across and 175 feet (53 m) high.

Geologic history

The area now occupied by the

Twin Cities Twin cities are a special case of two neighboring cities or urban centres that grow into a single conurbation – or narrowly separated urban areas – over time. There are no formal criteria, but twin cities are generally comparable in statu ...

of St. Paul and Minneapolis generally consisted of a 155 foot (47 m) thick layer of

St. Peter Sandstone The St. Peter Sandstone is an Ordovician geological formation. It belongs to the Chazyan stage of the Champlainian series in North American regional stratigraphy, equivalent to the late Darriwilian global stage. This sandstone originated as a sheet ...

, under a 16 foot (5 m) thick layer of

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

, under a 35 foot (11 m) thick layer of Platteville limestone. These layers were the result of an

Ordovician Period The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The ...

sea which covered east-central Minnesota 500 million years ago. The hard limestone cap was formed from fossilized

shell fish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environm ...

. About 20,000 years ago, the area was covered by the Superior Lobe of the

Laurentide Ice Sheet The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glacial epochs, from 2.58 million years a ...

, which left the St. Croix

moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

on the Twin Cities as it receded. Later the Grantsburg Sublobe of the Des Moines Lobe also covered the area. Under these vast layers of ice,

tunnel valley A tunnel valley is a U-shaped valley originally cut under the glacial ice near the margin of continental ice sheets such as that now covering Antarctica and formerly covering portions of all continents during past glacial ages. They can be as lo ...

s were formed, cutting through the limestone layer with tremendous force, to release ice meltwater and glacier effluence. The result was a series of troughs in the limestone, which were filled by glacial till and outwash deposit as the glaciers receded. Sometimes the sediment would be mixed with huge chunks of ice, which would leave voids in the soil, or kettles. These kettles created basins for the lakes of the Twin Cities, such as Harriet and

Bde Maka Ska Bde Maka Ska (, previously named Lake Calhoun, its former official designation) is the largest lake in Minneapolis, Minnesota, United States, and part of the city's Chain of Lakes. Surrounded by city park land and circled by bike and walking tra ...

. Connecting the city lakes in several north-south arteries are gorges cut through the bedrock, but filled with sand and sediment.

Glacial River Warren

When the great glacial River Warren began running 11,700 years ago, it cut a wide valley through central Minnesota, through the glacial till, but on top of the limestone layer. The

Minnesota River The Minnesota River ( dak, Mnísota Wakpá) is a tributary of the Mississippi River, approximately 332 miles (534 km) long, in the U.S. state of Minnesota. It drains a watershed of in Minnesota and about in South Dakota and Iowa. It ris ...

now runs in the valley created by the River Warren. When the river reached present-day

St. Paul Paul; grc, Παῦλος, translit=Paulos; cop, ⲡⲁⲩⲗⲟⲥ; hbo, פאולוס השליח (previously called Saul of Tarsus;; ar, بولس الطرسوسي; grc, Σαῦλος Ταρσεύς, Saũlos Tarseús; tr, Tarsuslu Pavlus; ...

, the massive volume of water quickly washed out the

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, sand, gravel, and sedimentary rock that had filled one of the troughs. The result was the Warren River Falls, plunging 175 feet (53 m) into a deep gorge. The turbulence caused by huge volumes of falling water washed out the sandstone underneath the falls, causing the thin limestone layer to break off in chunks. By 10,000 years ago, the waterfall had moved upstream to the confluence of the River Warren and the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

, adjacent to present-day

Fort Snelling Fort Snelling is a former military fortification and National Historic Landmark in the U.S. state of Minnesota on the bluffs overlooking the confluence of the Minnesota and Mississippi Rivers. The military site was initially named Fort Saint Anth ...

. By 9400 years ago, it had receded another two miles (3 km) up to Nine Mile Creek. At that point,

Lake Agassiz Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined. First postulated in 1823 by William H. Keating, it ...

broke through the ice to the north and began draining via the

Red River of the North The Red River (french: rivière Rouge or ) is a river in the north-central United States and central Canada. Originating at the confluence of the Bois de Sioux and Otter Tail rivers between the U.S. states of Minnesota and North Dakota, it fl ...

Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...

. River Warren then ceased to flow, but was succeeded by the much smaller

which drained a smaller

watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...

. It carried soil and sediment, but with much less energy than its predecessor. It was less able to transport those suspended materials, which precipitated out and left deposits. Eighty feet (24 m) of this

alluvium Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...

filled the river valley at Ft. Snelling, and 175 feet (53 m) were deposited at Saint Paul, refilling much of the gorge. The hydrology of the oversized valley was first explained by General G. K. Warren in 1868. He made a detailed survey of the valley in his search for possible transcontinental railroad routes. Posthumously, in appreciation of this work, the glacial river that was the outlet of Lake Agassiz was named River Warren.

Minneapolis waterfalls

When River Warren Falls receded past the confluence of River Warren with the much smaller

Upper Mississippi River The Upper Mississippi River is the portion of the Mississippi River upstream of St. Louis, Missouri, United States, at the confluence of its main tributary, the Missouri River. History In terms of geologic and hydrographic history, the Upper ...

, a new waterfall was created where the Mississippi entered the much-lower River Warren. Those new falls receded upstream on the Mississippi, migrating eight miles (13 km) over 9600 years to where

Louis Hennepin Father Louis Hennepin, O.F.M. baptized Antoine, (; 12 May 1626 – 5 December 1704) was a Belgian Roman Catholic priest and missionary of the Franciscan Recollet order (French: ''Récollets'') and an explorer of the interior of North Ameri ...

first saw it and named

St. Anthony Falls Saint Anthony Falls, or the Falls of Saint Anthony ( dak, italics=no, Owámniyomni, ) located at the northeastern edge of downtown Minneapolis, Minnesota, is the only natural major waterfall on the Mississippi River. Throughout the mid-to-late 1 ...

in 1680. Due to its value as a power source, this waterfall determined the location of

Minneapolis Minneapolis () is the largest city in Minnesota, United States, and the county seat of Hennepin County. The city is abundant in water, with thirteen lakes, wetlands, the Mississippi River, creeks and waterfalls. Minneapolis has its origins ...

. One branch of the river coming from the west,

Minnehaha Creek Minnehaha Creek ( dak, Mniȟáȟa Wakpádaŋ) is a 22-mile-long (35 km) tributary of the Mississippi River that flows east from Gray's Bay Dam on Lake Minnetonka through the suburban cities of Minnetonka, Hopkins, Saint Louis Park, and Edin ...

receded only a few hundred yards from one of the channels of the Mississippi.

Minnehaha Falls Minnehaha Park is a city park in Minneapolis, Minnesota, United States, and home to Minnehaha Falls and the lower reaches of Minnehaha Creek. Officially named Minnehaha Regional Park, it is part of the Minneapolis Park and Recreation Board syst ...

remains as a picturesque and informative relic of River Warren Falls, and the limestone-over-sandstone construction is readily apparent in its small gorge.

References

{{Reflist Waterfalls of Minnesota Historical geology Geography of Saint Paul, Minnesota Geology of Minnesota Landforms of Ramsey County, Minnesota Landforms of Hennepin County, Minnesota Mississippi Gorge