A reconnaissance study of radon levels in soils developed on the Upper Cretaceous Pierre Shale just above the Sharon Springs Member in the Missouri River valley in southeastern South Dakota and northeastern Nebraska

Northeast Nebraska barbed tributaries include north-oriented streams flowing to the south-oriented Missouri River and south-oriented streams flowing to the north-oriented Missouri River tributaries. Detailed topographic maps were used to determine how these northeast Nebraska drainage routes originated. A giant south-oriented supra-glacial melt water river is interpreted to have sliced an ice-walled and bedrock-floored canyon into a decaying ice sheet’s surface where eastern South Dakota’s east-facing Missouri Escarpment and west-facing Prairie Coteau escarpment are now located and to have flowed from that canyon’s mouth across northeast Nebraska while South Dakota’s north-facing Pine Ridge Escarpment is interpreted to be the south wall of a large east-oriented valley that was eroded headward across immense southeast-oriented ice-marginal melt water floods which had originally flowed across northeast Nebraska. Prior to Missouri River valley headward erosion these two different immense melt water floods created and then flowed across a low relief and low gradient northeast Nebraska topographic surface. Present day northeast Nebraska topography developed when the deep south-oriented Missouri River valley and its south-oriented tributary valleys eroded headward into this low relief and low gradient topographic surface. As the deep Missouri River valley eroded headward it beheaded shallow south-oriented flood flow channels supplying water to new and actively eroding south-oriented Missouri River tributary valleys and water on north ends of the beheaded channels reversed flow direction to move toward the much deeper Missouri River valley. Water still moving in south directions adjacent to these reversed flow channels was then captured leading to development of south-oriented tributaries to the north-oriented streams.

Download Full-text

A Second Sexually Aberrant Specimen of Dakoticancer Overanus Rathbun, 1917, From the Upper Cretaceous Dakoticancer Assemblage, Pierre Shale, South Dakota (Decapoda, Brachyura)

Crustaceana ◽

10.1163/156854083x00028 ◽

1983 ◽

Vol 44 (1) ◽

pp. 23-26 ◽

Cited By ~ 4

Author(s):

Gale A. Bishop

Keyword(s):

South Dakota ◽

Upper Cretaceous ◽

Pierre Shale

Download Full-text

Fort d’Orléans and the Grotton–St. Ange Family

10.5406/illinois/9780252038976.003.0001 ◽

2017 ◽

Author(s):

Carl J. Ekberg ◽

Sharon K. Person

Keyword(s):

Missouri River ◽

River Valley ◽

Military Family ◽

Half Century ◽

Illinois Country ◽

History Of ◽

Missouri River Valley ◽

The One

This chapter shows that the Grotton–St. Ange family was the most important political and military family in Upper Louisiana for the half century between 1720 and 1770. Louis St. Ange de Bellerive first came to prominence under the sponsorship of his father, Robert Grotton St. Ange. Shortly after Robert Grotton St. Ange's marriage to his second wife, Élisabeth Chorel, in 1718, the couple and Robert's two sons by his first wife, Pierre and Louis, headed west to establish the St. Anges as a leading family in the Illinois Country. This chapter traces the history of the Grotton–St. Ange family in the Illinois Country and looks at the expeditions of Étienne Veniard de Bourgmont, the first white man to ascend the Missouri River valley in 1714 and the one who built Fort d'Orléans. It also considers the presence of the St. Ange family at Fort d'Orléans, where Louis St. Ange de Bellerive replaced Robert Grotton St. Ange as commandant.

Download Full-text