Abstract:

The Republican River-Prairie Dog Creek drainage divide area in Furnas and Harlan Counties, Nebraska and Norton and Phillips County, Kansas was eroded by massive south-oriented flood flow. Flood waters were probably derived from a rapidly melting North American ice sheet and flowed south across Nebraska and into Kansas. Missouri River tributary valleys eroded headward into Kansas and Nebraska in an identifiable sequence to capture the immense south-oriented flood flow and divert flood waters to the newly eroded Missouri River valley. The Republican River valley eroded headward from what was then the newly eroded Kansas River valley to capture the south-oriented flood flow. The east-northeast oriented Prairie Dog Creek valley then eroded headward from the actively eroding Republican River valley head to capture the south-oriented flood flow. Soon thereafter the east-northeast oriented Sappa Creek valley eroded headward from the actively eroding Republican River valley to behead south-oriented flood flow to the newly eroded Prairie Dog Creek valley. Next the east-northeast oriented Beaver Creek valley eroded headward from the newly eroded Sappa Creek valley to behead south-oriented flood flow to the newly eroded Sappa Creek valley. Finally headward erosion of the deep east-oriented Republican River valley beheaded south-oriented flood flow to the newly eroded Beaver Creek valley. Evidence supporting this flood origin interpretation includes present day valley orientations and positions and also numerous north-south oriented through valleys crossing the Republican River-Beaver Creek, Beaver Creek-Sappa Creek, and Sappa Creek-Prairie Dog Creek drainage divides.

Preface:

• The purpose of this essay is to use topographic map interpretation methods to explore Republican River-Prairie Dog Creek drainage divide area landform origins in Furnas and Harlan Counties, Nebraska and Norton and Phillips Counties, Kansas, USA. Map interpretation methods can be used to unravel many geomorphic events leading up to formation of present-day drainage routes and development of other landform features. While each detailed topographic map feature provides detailed evidence to be explained, the solution must be consistent with explanations for adjacent area map evidence as well as solutions to big picture map evidence puzzles. I invite readers to improve upon my solutions and/or to propose alternate solutions that better explain evidence and are also consistent with adjacent map area and big picture evidence. Readers may do so either by making comments here or by writing and publishing their own essays and then by leaving a link to those essays in a comment here.

• This essay is also exploring a new geomorphology paradigm in which erosional landforms are interpreted as evidence left by immense glacial melt water floods. Implied in that interpretation is the immense floods were derived from a thick North American ice sheet that created a deep “hole” in the North American continent and also melted fast. The previously unexplored paradigm being tested in this and other Missouri River drainage basin landform origins research project essays is a thick North American ice sheet, comparable in thickness to the Antarctic ice sheet, occupied the North American region usually recognized to have been glaciated, and through its weight and erosive actions created a deep North American “hole”. The southwestern rim of that deep “hole” is today preserved in the high Rocky Mountains. The ice sheet through its weight and deep erosion (and perhaps deposition along major south-oriented melt water flow routes) caused significant crustal warping and tectonic change, through its action of melting fast produced immense floods that flowed across the continent, and through its action of melting fast systematically opened up space in the ice sheet created “hole” so headward erosion of newly developed north-oriented drainage systems captured immense south-oriented melt water floods and diverted the floods north into space the ice sheet had once occupied.

• If this previously unexplored paradigm is correct the geographic region explored by this essay should contain evidence of immense floods that were captured by headward erosion of new valley systems so as to cause the floods to flow in a different direction. Ability of this previously unexplored paradigm to explain Republican River-Prairie Dog Creek drainage divide area landform origins in Furnas and Harlan Counties, Nebraska and Norton and Phillips Counties, Kansas will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm. This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Republican River-Prairie Dog Creek drainage divide area location map

Figure 1: Republican River-Prairie Dog Creek drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 provides a location map the Republican River-Prairie Dog Creek drainage divide area in Furnas and Harlan Counties, Nebraska and Norton and Phillips Counties, Kansas. Nebraska is the state located in the figure 1 north half and Kansas is located in the figure 1 south half. The Republican River flows from the figure 1 west center edge (just north of the state line) in an east-northeast direction to Benkelman, McCook, Cambridge, Holbrook, and Arapahoe, Nebraska. At Arapahoe the Republican River turns to flow in a southeast and east direction to Edison, Oxford, Orleans and Alma, Nebraska before entering Harlan County Lake, which is a reservoir flooding the Republican River valley. Downstream from Harlan County Lake the Republican River flows in an east direction to Naponee, Franklin, Riverton, and Red Cloud, Nebraska before reaching the figure 1 east edge. East of figure 1 the Republican River turns to flow in a south-southeast, east, and south-southeast direction to join the east-oriented Kansas River. The Platte River is located north of the Republican River and in figure 1 can be seen flowing from Wizard Island near the figure 1 north center edge in a southeast direction to Kearney and then flowing in a northeast direction to the figure 1 northeast corner. East of figure 1 the Platte River flows in a generally east direction to join the south-southeast oriented Missouri River. The south-southeast oriented Missouri River joins the east-oriented Kansas River at Kansas City, Missouri and then flows in a generally east-southeast direction to join the south-oriented Mississippi River at Saint Louis, Missouri. South of the Republican River drainage basin in figure 1 is the North Fork Solomon River. The North Fork Solomon River originates near the figure 1 southwest corner and flows in an east-northeast direction to New Almelo, Lenora, Edmond, and Kirwin, Kansas before turning to flow in a southeast direction to Gaylord, Portis, and Downs, Kansas before reaching the figure 1 east edge. East of figure 1 the North Fork Solomon River joins the South Fork to form the southeast-oriented Solomon River, which flows to the east-oriented Kansas River. Prairie Dog Creek is a northeast-oriented Republican River tributary located just north of the North Fork Solomon River. Prairie Dog Creek also originates near the figure 1 southwest corner and flows to Jennings, Clayton, Norton, Almena, and Long Island, Kansas before joining the Republican River at Harlan County Lake. Between the Republican River and Prairie Dog Creek are two other prominent northeast-oriented Republican River tributaries. Sappa Creek and its northeast-oriented tributary, Beaver Creek, are important to the discussion here. The Republican River-Prairie Dog Creek drainage divide area in Furnas and Harlan Counties, Nebraska and Norton and Phillips Counties, Kansas is generally located south of the Republican River segment between Cambridge, Nebraska and Harlan County Lake and north of the Prairie Dog Creek segment downstream from Clayton, Kansas. Hundreds of Missouri River drainage basin landform origins research project essay (published on this website) collectively have presented substantial evidence for immense south-oriented floods, which flowed across Nebraska and Kansas. Flood waters were probably derived from a rapidly melting thick North American ice sheet.

Republican River-Prairie Dog Creek drainage divide area detailed location map

Figure 2: Republican River-Prairie Dog Creek drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 2 provides a more detailed location map for the Republican River-Prairie Dog Creek drainage divide area in Furnas and Harlan Counties, Nebraska and Norton and Phillips Counties, Kansas. Red Willow, Furnas, Harlan, and Franklin are Nebraska county names and the county boundaries are shown. Decatur, Norton, and Phillips are Kansas County names. The Republican River flows from the figure 2 west edge to McCook in Red Willow County and then in an east-northeast direction to Holbrook and Arapahoe in northern Furnas County. From Arapahoe the Republican River flows in a southeast direction to Harlan County Lake. Downstream from the Harlan County Lake Dam the Republican River flows in an east direction to the figure 2 east edge. Prairie Dog Creek flows in a northeast direction across southern Decatur County to Norton and Almena in Norton County and to Long Island in northwest Phillips County before flowing into Nebraska and joining the Republican River at Harlan County Lake. North of Prairie Dog Creek is northeast oriented Sappa Creek, which flows from the figure 2 west edge across Decatur County to the Norton County northwest corner before flowing into southern Furnas County and joining northeast and east oriented Beaver Creek near the Furnas County-Harlan County border. Beaver Creek flows in a northeast direction across the Decatur County northwest corner and the Red Willow County southeast corner before flowing to Wilsonville, Hendley, and Beaver City in Furnas County and joining northeast-oriented Sappa Creek near the Harlan County border. Once in Harlan County Sappa Creek flows in an east direction to join the southeast-oriented Republican River near Orleans. Note south-southeast oriented and north and north-northwest oriented Prairie Dog Creek, Sappa Creek, Beaver Creek, and Republican River tributaries. These tributaries provide evidence the Prairie Dog Creek, Sappa Creek, Beaver Creek, and Republican River valleys eroded headward in that sequence to capture flood waters moving in multiple south and/or south-southeast oriented flood flow channels such as might be found in a large-scale south-oriented anastomosing channel complex. Topographic maps below better illustrate the evidence. A previous essay described the region immediately north of the Republican River valley and is the Platte River-Republican River drainage divide area in Gosper and Furnas Counties, Nebraska essay which can be found under Republican River on the sidebar category list.

Sappa Creek-Prairie Dog Creek drainage divide area east end

Figure 3: Beaver Creek-Prairie Dog Creek drainage divide area east end. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 3 illustrates the Sappa Creek-Prairie Dog Creek and the Republican River-Prairie Dog Creek drainage divide area immediately west of Harlan County Lake. Alma, Nebraska is the town near the figure 3 northeast corner. Orleans is the town located just east of the figure 3 north center edge. The Republican River flows in an east-southeast direction from the figure 3 north center edge to the figure 3 east edge and Harlan County Lake floods much of the figure 3 Republican River valley. Sappa Creek is the east-oriented Republican River tributary located near the figure 3 north edge (west half). Prairie Dog Creek is the east-northeast oriented Republican River tributary located in the figure 3 south center area and southeast quadrant. Prairie Dog Creek joins the Republican River in Harlan County Lake just east of the figure 3 map area. Note the north and north-north-northwest oriented Republican River and Sappa Creek tributary valleys. Also note the south-southeast oriented Prairie Dog Creek tributary valleys. Further note how the north-oriented tributary valleys are linked by shallow through valleys with the south-oriented tributary valleys. Generally the through valleys show as only being one contour line in depth, although a few of the through valleys are two or more contour lines in depth. Contour lines are at 10-meter intervals. While not deep the through valleys are evidence of multiple south and south-southeast oriented flood flow channels that once crossed the figure 3 map area. At that time the deep Republican River and Sappa Creek valleys did not exist and elevations north of the figure 3 map area were at least as high, if not higher, than the present day Republican River (and Sappa Creek)-Prairie Dog Creek drainage divide. Flood waters were flowing to what was then the actively eroding east-northeast oriented Prairie Dog Creek valley, which was eroding headward from what was then the actively eroding Republican River valley head. The Republican River valley had eroded headward into the figure 3 map area from what was then the newly eroded Kansas River valley to capture the massive south-oriented flood flow and to divert flood waters to the newly eroded Kansas and Missouri River valleys. Headward erosion of the Republican River valley and its tributary Sappa Creek valley beheaded south-oriented flood flow channels to the newly eroded Prairie Dog Creek valley. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north and erode the north-oriented Republican River and Sappa Creek tributary valleys.

Sappa Creek-Prairie Dog Creek drainage divide area north of Almena, Kansas

Figure 4: Sappa Creek-Prairie Dog Creek drainage divide area north of Almena, Kansas. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 4 illustrates the Sappa Creek-Prairie Dog Creek drainage divide area north of Almena, Kansas and is located west and south of the figure 3 map area. Almena is the town located just east of the figure 4 south center edge area. The east-northeast oriented stream in the figure 4 southeast quadrant is Prairie Dog Creek. The northeast and east oriented stream in the figure 4 northwest quadrant is Sappa Creek. Note the north-oriented Sappa Creek tributaries. Regardless of tributary orientations many of the north-oriented tributaries have north-northwest oriented tributaries or headwaters. Note also the south-oriented Prairie Dog Creek tributaries. Nearly all of these Prairie Dog Creek tributaries have south-southeast oriented valley segments. Further note how the north-oriented Sappa Creek tributary valleys are again linked by shallow through valleys with the south-oriented Prairie Dog Creek tributary valleys. The through valleys are again evidence of multiple south-oriented flood flow channels, which once crossed the figure 4 map area. Flood waters originally were continuing south to what was then the newly eroded North Fork Solomon River valley, which is located south of the figure 4 map area and flood waters were flowing on a topographic surface at least as high as the present day Sappa Creek-Prairie Dog Creek drainage divide. Headward erosion of the deep east-northeast oriented Prairie Dog Creek valley from the newly eroded Republican River valley then captured the south-oriented flood flow and diverted flood waters to the Republican River valley. Sappa Creek valley headward erosion from the actively eroding Republican River valley then beheaded south-oriented flow channels to the newly eroded Prairie Dog Creek valley. Flood flow channels were beheaded one channel at a time from east to west. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north to the newly eroded Sappa Creek valley. Because flood flow channels were anastomosing or interconnected reversed flow in a newly beheaded flood flow channel could capture yet to be beheaded flood flow from channels further to the west. Such captures provided water volumes required to erode the north-oriented Sappa Creek tributary valleys and movements of captured flood flow explain the origin of the northeast-oriented Sappa Creek tributaries and tributary valley segments. Reversal of flood flow on north ends of beheaded flood flow channels was responsible for creating the present day Sappa Creek-Prairie Dog Creek drainage divide.

Sappa Creek-Prairie Dog Creek drainage divide northwest of Norton, Kansas

Figure 5: Sappa Creek-Prairie Dog Creek drainage divide northwest of Norton, Kansas. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 5 illustrates the Sappa Creek-Prairie Dog Creek drainage divide area northwest of Norton, Kansas and west and south of the figure 4 map area. Norton is the town located in the figure 5 southeast corner. Norcatur is the smaller town located near the figure 5 southwest corner. Prairie Dog Creek is the east-northeast oriented stream at Norton. Sappa Creek is the east-northeast oriented stream in the figure 5 northwest quadrant and north center edge area. Long Branch is the northeast and north oriented Sappa Creek tributary north of Norcatur. Note again the south and south-southeast oriented Prairie Dog Creek tributaries and the north and north-northwest oriented Sappa Creek tributaries. Also note how Long Branch has north-northwest oriented tributaries as well. Again note how shallow through valleys link the north and north-northwest oriented Sappa Creek and Long Branch tributary valleys with the south and south-southeast oriented Prairie Dog Creek tributary valleys. Similar through valleys are present on the Sappa Creek-Long Branch drainage divide. The through valleys provide evidence of south and/or south-southeast oriented flood flow across the entire figure 5 map area on a topographic surface at least as high as the present day Sappa Creek-Prairie Dog Creek drainage divide. Headward erosion of the deep east-northeast oriented Prairie Dog Creek valley captured the south-oriented flood flow and diverted flood waters to the newly eroded Republican River valley. Next headward erosion of the deep Sappa Creek valley-Long Branch valley beheaded the south-oriented flood flow channels. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north to the newly eroded and deep Sappa Creek valley. Headward erosion of the Sappa Creek valley next beheaded south-oriented flood flow to the newly eroded Long Branch valley and the process was repeated.

Republican River-Beaver Creek drainage divide area south of Arapahoe, Nebraska

Figure 6: Republican River-Beaver Creek drainage divide area south of Arapahoe, Nebraska. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 6 illustrates the Republican River-Beaver Creek drainage divide area south of Arapahoe, Nebraska and is located west and north of the figure 3 map area. The Republican River is the east-southeast oriented river located in the figure 6 north margin area and flows from the figure 6 northwest corner area to the figure 6 east edge. Beaver Creek is the east-northeast and southeast oriented stream flowing from the figure 6 southwest corner to the figure 6 southeast corner. The south edge of Arapahoe, Nebraska is located where the north-south oriented highway crosses the figure 6 north edge (west half). Oxford is the Nebraska town located near where the Republican River crosses the figure 6 east edge. Edison is the small town located in the Republican River valley between Arapahoe and Oxford. Hendley is the town located in the figure 6 southwest corner. Beaver City is the larger town located in the figure 6 south center area and Hollinger is the small town located where east-northeast oriented Beaver Creek turns to flow in a southeast direction. Crum Creek is the north-, east-, and north-oriented tributary joining the Republican River south of Arapahoe. Note the long south-southeast and south oriented Beaver Creek tributaries and the relatively short north-oriented Republican River tributaries. Like with the Sappa Creek-Prairie Dog Creek drainage divides to the south of figure 6 the Republican River-Beaver Creek drainage divide is crossed by multiple shallow north-south oriented through valleys linking north-oriented Republican River tributary valleys with south-oriented Beaver Creek tributary valleys. The through valleys are evidence of south-southeast oriented anastomosing flood flow channels that once moved immense volumes of flood water across the figure 6 map area. At that time the deep Republican River valley did not exist. Headward erosion of the deep Beaver Creek valley first captured the south-oriented flood flow in the figure 6 map area. Republican River valley headward erosion was close behind and beheaded the south-oriented flood flow channels to the newly eroded Beaver Creek valley. Flood waters on north ends of beheaded flood flow channels reversed flow to flow north, eroded the north-oriented Republican River tributary valleys, and created the Republican River-Beaver Creek drainage divide.

Beaver Creek-Sappa Creek drainage divide area south of Beaver City

Figure 7: Beaver Creek-Sappa Creek drainage divide area south of Beaver City, Nebraska. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 7 illustrates the Beaver Creek-Sappa Creek drainage divide area south of the figure 6 map area and north of the figure 4 map area and includes overlap areas with figures 4 and 6. Hollinger is the small town located in the figure 7 northeast corner. Beaver City is the larger town located in the figure 7 north center area. Hendley is the town located near the figure 7 west edge (north half). Beaver Creek flows in an east and east-northeast direction from Hendley to Beaver City and then to Hollinger in the figure 7 northeast corner. Sappa Creek is located in the figure 7 south half and flows in an east-northeast direction from the figure 7 southwest corner to the figure 7 east edge. Note again the north-oriented Beaver Creek tributaries and the south and south-southeast oriented Sappa Creek tributaries. Further note the multiple north-south oriented shallow through valleys linking the north-oriented Beaver Creek tributary valleys with the south-oriented Sappa Creek tributary valleys. The through valleys are further evidence of the south-southeast oriented anastomosing channel complex that once moved massive volumes of south-oriented flood water across the entire Republican River-Prairie Dog Creek drainage divide area. Initially flood waters were moving to what was then the newly eroded North Fork Solomon River valley, although headward erosion of the deep east-northeast oriented Prairie Dog Creek valley south of the figure 7 map area (see figure 4) captured the south-oriented flood flow and diverted flood waters to the newly eroded Republican River. Next headward erosion of the Sappa Creek valley beheaded and reversed flood flow to the newly eroded Prairie Dog Creek valley as discussed in figures 3, 4, and 5. Then Beaver Creek valley headward erosion beheaded and reversed flood flow to the newly eroded Sappa Creek valley as can be seen here in figure 7. Finally headward erosion of the deep Republican River valley beheaded and reversed flood flow to the newly eroded Beaver Creek valley (as seen in figure 6).

Republican River-Beaver Creek drainage divide area south of Cambridge

Figure 8: Republican River-Beaver Creek drainage divide area south of Cambridge. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 8 illustrates the Republican River-Beaver Creek drainage divide area south and east of Cambridge, Nebraska and west of the figure 6 map area and includes overlap areas with figure 6. Arapahoe, Nebraska is located just north of the figure 8 northeast corner. The south edge of Holbrook is located about six miles west of Arapahoe along the figure 8 north edge. Cambridge, Nebraska is located in the figure 8 northwest quadrant. The Republican River flows from the figure 8 west edge in an east-northeast direction to Cambridge and Holbrook and then in an east direction to Arapahoe and the figure 8 northeast corner. East-northeast oriented Beaver Creek can just barely be seen in the figure 8 southeast quadrant. Hendley is the small town located in the Beaver Creek valley. Again note the relatively long south-southeast oriented Beaver Creek tributaries and the somewhat shorter north-oriented Republican River tributaries. The figure 8 Republican River-Beaver Creek drainage divide area is again crossed by numerous north-south oriented shallow through valleys. The through valleys are again evidence of a south-southeast oriented anastomosing channel complex that once moved flood water across the entire figure 8 map area prior to headward erosion of the deep Republican River valley. The deep Beaver Creek valley eroded headward into the figure 8 map region to capture the south-oriented flood flow and to divert flood waters to what was then the newly eroded Republican River valley east of the figure 8 map area. The south-southeast oriented Beaver Creek tributary valleys then began to erode headward from the newly eroded east-northeast oriented Beaver Creek valley. Headward erosion of the deep Republican River valley then beheaded south-oriented flood flow channels in sequence, from east to west. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north to the newly eroded and deep Republican River valley. Reversed flood flow was responsible for eroding the north-oriented Republican River tributary valleys and for creating the Republican River-Beaver Creek drainage divide.

Beaver Creek-Sappa Creek south of Wilsonville, Nebraska

Figure 9: Beaver Creek-Sappa Creek south of Wilsonville, Nebraska. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 9 illustrates the Beaver Creek-Sappa Creek drainage divide area south of Wilsonville and is located south of the figure 8 map area and north and slightly west of the figure 5 map area. Beaver Creek is the east-northeast oriented stream near the figure 9 north edge. Wilsonville is the town located in the Beaver Creek valley near the figure 9 north edge. Sappa Creek is the east-northeast oriented stream located in the figure 9 south half. Note again south-southeast oriented Sappa Creek tributaries and north and north-northwest oriented Beaver Creek tributaries. Shallow north-northwest to south-south-southeast oriented through valleys link headwaters of the north-oriented Beaver Creek tributaries with headwaters of the south-oriented Sappa Creek tributaries. The through valleys are again evidence of the south-southeast oriented anastomosing channel complex that once moved flood waters from north of the figure 9 map area to what were then actively eroding south-southeast oriented Sappa Creek tributary valleys. At that time the deep Beaver Creek valley did not exist, nor did the deep Republican River valley exist north of the figure 9 map area. Flood waters flowed on a topographic surface at least as high as the present day Beaver Creek-Sappa Creek drainage divide. Beaver Creek valley headward erosion probably closely followed Sappa Creek valley headward erosion and beheaded south-southeast oriented flood flow channels moving flood waters to what were then actively eroding south-southeast oriented Sappa Creek tributary valleys. Flood flow channels were beheaded in sequence from the east to the west. Flood waters on north ends of beheaded flood flow channels reversed flow direction to flow north to the newly eroded Beaver Creek valley. The reversed flood flow with the aid of captured yet to beheaded flood flow from flood flow further to the west eroded the north-oriented Beaver Creek tributary valleys and created the Beaver Creek-Sappa Creek drainage divide. Figure 10 below provides a detailed map of the drainage divide south of Wilsonville to better illustrate the through valleys.

Detailed map of Beaver Creek-Sappa Creek drainage divide area south of Wilsonville

Figure 10: Detailed map of Beaver Creek-Sappa Creek drainage divide area south of Wilsonville. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

Figure 10 provides a detailed map of the Beaver Creek-Sappa Creek drainage divide area south of Wilsonville, which was seen in less detail in figure 9 above. North and north-northwest oriented streams in the figure 10 north half are Beaver Creek tributaries. South and south-southeast oriented streams flowing to the figure 10 south edge are Sappa Creek tributaries. The map contour interval is ten feet. Note the multiple north-south oriented through valleys linking north-oriented Beaver Creek tributary valleys with south-oriented Sappa Creek tributary valleys. The through valleys are shallow when compared with depths of tributary valleys on either side, but the through valleys do provide evidence of former flood water eroded valleys. The flood water was moving in a south-southeast direction to what were then actively eroding south-southeast oriented tributary valleys to what was then the newly eroded east-northeast oriented Sappa Creek valley. Water was moving across the entire the Beaver Creek-Sappa Creek drainage divide area in multiple south-southeast oriented flood flow channels, suggestive of a large-scale south-oriented anastomosing channel complex. At that time there was no Beaver Creek valley north of the figure 10 map area and there was no Republican River further to the north. In fact all present day Missouri River tributary valleys (and the Missouri River valley itself) north and west of the figure 10 map area had yet to be eroded. The Missouri River drainage basin valleys north and west of the figure 10 map area were eroded headward in an identifiable sequence. Prior to Sappa Creek valley headward erosion the Prairie Dog Creek valley had eroded headward to the south of the Sappa Creek valley. Following headward erosion of the Sappa Creek valley south of the figure 10 map area the next major valley eroded in this region was the east-northeast oriented Beaver Creek valley north of the figure 10 map area. Following Beaver Creek valley headward erosion the deep Republican River valley eroded west and ended all south-oriented flood flow across the present day Republican River-Prairie Dog Creek drainage divide area.

Additional information and sources of maps

This essay has only provided a sample of the drainage divide evidence supporting the “thick ice sheet that melted fast” geomorphology paradigm. Many additional examples could be provided, especially by using more detailed topographic maps. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of supporting data. Maps used in this study were created by the United States Geological Survey and can be purchased in hard copy from the United States Geological Survey or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories located in major research libraries and elsewhere throughout the United States and in other countries. Illustrations used in this essay were created using National Geographic Society TOPO software and digital data. National Geographic Society digital maps can be purchased from the National Geographic Society or from dealers offering National Geographic Society digital maps.