Abstract:

The Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties, Missouri is located south of the Osage River and east of the Sac River and is drained primarily by north and northwest oriented streams. The north and northwest oriented stream valleys were eroded during a massive reversal of an immense south-oriented flood. The south oriented flood was derived from a rapidly melting North American ice sheet and was flowing south across the St Clair, Hickory, Cedar, and Polk County area to south oriented tributary valleys which had eroded headward from what was then the newly eroded southeast oriented White River valley. A massive reversal of the south-oriented flood flow was triggered by headward erosion of the deep east-oriented Missouri River-Osage River valley which beheaded the south oriented flood flow routes in sequence from east to west. Flood waters on north ends of beheaded flood flow routes reversed flow direction to flow north to the newly eroded and deep Osage River valley and eroded deep north-oriented valleys. These deep north oriented valleys captured flood flow from south-oriented flood flow routes west of the actively eroding Osage River valley head, which resulted in captured flood water moving in southeast, east, and northeast directions to actively eroding north oriented valleys. As the deep Osage River valley head eroded west new north-oriented valleys eroded headward (or south) and beheaded southeast-oriented flood flow routes moving captured flood flow to north valleys located further east. Flood waters on northwest ends of the beheaded southeast-oriented flood flow routes reversed flow direction to erode northwest-oriented valleys. Evidence supporting this flood origin interpretation includes positions and orientations of modern-day stream valleys and numerous through valleys eroded across present day drainage divides.

Preface:

The following interpretation of detailed topographic map evidence is provided as evidence in the Missouri River drainage basin landform origins research project, which is compiling similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with and within certain adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored geomorphology paradigm, which is briefly described in the introduction below. Project essays available at this site may be found by selecting desired Missouri River tributaries and/or states from this essay’s sidebar category list.

• The purpose of this essay is to use topographic map interpretation methods to explore Weaubleau Creek-Little Sac River drainage divide area landform origins in St Clair, Hickory, Cedar, and Polk Counties, Missouri, 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 topographic map evidence in the Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties, Missouri will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Weaubleau Creek-Little Sac River drainage divide area location map

Figure 1: Weaubleau Creek-Little Sac River 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 for the Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties, Missouri and illustrates a region in southwest Missouri. Springfield is the largest city in southwest Missouri. The Osage River is formed at the confluence of tributaries near Schell City and flows in an east and northeast direction to Harry S. Truman Reservoir in the figure 1 northwest quadrant. From Harry S. Truman Reservoir the Osage River flows to the Lake of the Ozarks (another large reservoir flooding the Osage River valley) and then in a northeast direction to the figure 1 north edge. North of the figure 1 map area the Osage River joins the Missouri River, which then flows in an east direction to join the south-oriented Mississippi River. The Sac River is a northwest and north oriented tributary originating near Republic (west of Springfield) and joining the Osage River near Osceola (on south edge of Harry S. Truman Reservoir). The lake south of Stockton flooding the Sac River valley is Stockton Lake and is another large reservoir. The Little Sac River flows in a north-northwest and northwest direction from near Springfield to join the Sac River at Stockton Lake. East of the Little Sac River is northwest and north-oriented Pomme de Terre River, which joins the Osage River at Harry S. Truman Reservoir. Weaubleau Creek is unlabeled in figure 1, but is the northwest-oriented stream at the north end of the Sac River-Pomme de Terre River drainage divide area and flows near the town of Weaubleau to join the Osage River east of Osceola. South-oriented streams along the figure 1 south edge flow to the southeast-oriented White River, which flows eventually to the south-oriented Mississippi River. The Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties illustrated and discussed in this essay is located south of Weaubleau Creek, east of the Sac River, west of the Pomme de Terre River, and north of the northwest-oriented Little Sac River segment east of Stockton Lake and is one of several hundred Missouri River drainage basin landform origins research project essays. As a group these essays present evidence for immense south oriented floods from a rapidly melting North American ice sheet which flowed into and across the figure 1 map area. Initially flood waters flowed south across the figure 1 map area to what were then actively eroding south-oriented White River tributary valleys which were eroding headward from what was then the newly eroded White River valley. Headward erosion of the deep Missouri River-Osage River valley then beheaded the south-oriented flood flow routes and triggered a massive flood flow reversal. The flood flow reversal eroded the north-oriented Osage River tributary valleys and created the Osage River-White River drainage divide, which is also the divide between the Missouri River drainage basin to the north and the White River drainage basin to the south.

Weaubleau Creek-Little Sac River drainage divide area detailed location map

Figure 2: Weaubleau Creek-Little Sac River 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 Weaubleau Creek-Little Sac River drainage divide area in St Clair, Hickory, Cedar, and Polk Counties, Missouri. County names and boundaries are shown along with relevant areas of St Clair, Hickory, Cedar, and Polk Counties. The Osage River flows in an east and northeast direction in St Clair County near the figure 2 north edge. The meandering Sac River flows north from Stockton Lake in Cedar County to join the Osage River just south of Osceola in St Clair County. The Little Sac River flows in a northwest direction across the Polk County southwest quadrant and joins the Sac River in southern Cedar County. Bear Creek is a northwest oriented Sac River tributary originating south of Bolivar in Polk County and joining the Sac River north of the dam impounding the Stockton Lake reservoir. North of Bear Creek is Turkey Creek, which is a northwest-oriented Sac River tributary originating in northeast Cedar County and joining the Sac River near the Cedar County-St Clair County border. North of Turkey Creek is northwest oriented Brush Creek, which originates in northwest Polk County and which joins the Sac River in southern St Clair County. Coon Creek is the northwest-oriented Sac River tributary north of Brush Creek and originates near Collins in southeast St Clair County. Weaubleau Creek originates near Rondo in northern Polk County and flows north into southwest Hickory County where it turns to flow in a northwest direction into St Clair County and then north to join the Osage River a short distance downstream from Osceola. The northwest and north oriented South Fork is the major Weaubleau Creek tributary shown. The north and northwest-oriented drainage routes shown in figure 2 were formed following a massive reversal of south-oriented flood flow triggered by headward erosion of the deep east-oriented Osage River valley. Flood waters prior to the flow reversal were flowing from a rapidly melting North American ice sheet (north of the figure 2 map area) to what were at that time actively eroding south-oriented White River tributary valleys, which had eroded headward from what was at that time the newly eroded southeast-oriented White River valley. Headward erosion of the deep Osage River valley beheaded the south-oriented flood flow routes in sequence from east to west. Flood waters on north ends of beheaded flood flow routes reversed flow direction and began to erode north-oriented Osage River tributary valleys. These new and deep north-oriented tributary valleys often captured yet to be beheaded flood flow from flood flow routes west of the actively eroding Osage River valley head. This captured flood water provided water volumes required to erode the long and deep north-oriented Osage River tributary valleys seen today, many of which follow routes initially established by south-oriented flood flow.

Sac River-Weaubleau Creek drainage divide area

Figure 3: Sac River-Weaubleau Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Sac River-Weaubleau Creek drainage divide area south of the Osage River. Osceola is the town located in the figure 3 north center area. Osage Heights and Roscoe are the smaller towns located along the west edge just south of the figure 3 west center edge. Vista is the even smaller town near the figure 3 center. The Osage River meanders in a northeast direction from Osage Heights to Osceola and then to the figure 3 north edge (east half). The Sac River meanders in a north direction from the figure 3 south edge (west half) to join the Osage River near the Sac Osage State Wildlife Area. Coon Creek is the northwest oriented tributary flowing from the figure 3 south center edge to join the Sac River east of Roscoe. Weaubleau Creek flows in a northwest direction from the figure 3 southeast corner before turning to flow in a north direction to join the Osage River near the figure 3 north edge. The South Fork Weaubleau Creek flows north from the figure 3 south edge to join Weaubleau Creek in the figure 3 southeast quadrant. Tanyard Branch is a northeast-oriented Weaubleau Creek tributary located southeast from Vista. Brush Creek originates near Vista and flows north to join the Osage River near the figure 3 north edge. The Osage River, Sac River, and Weaubleau Creek all have prominent incised meanders, which is interpreted here to mean their valleys were rapidly eroded by immense volumes of flood water. Figure 3 drainage history began with immense south and/or southeast oriented floods flowing across the entire figure 3 map area on a topographic surface at least as high the highest figure 3 elevations today. Headward erosion of the deep northeast-oriented Osage River valley beheaded the south-oriented flood flow routes in sequence from east to west and triggered a flood flow reversal as flood waters on north ends of beheaded flood flow routes reversed flow direction to erode north-oriented Osage River tributary valleys. Because flood flow routes were beheaded one at a time from east to west and because flood flow routes were interconnected or anastomosing reversed flood flow in a newly beheaded flood flow channel could capture yet to be beheaded south-oriented flood flow from channels west of the actively eroding Osage River valley head. Capture of such yet to be beheaded flood flow routes provided immense quantities of flood water to help erode the newly reversed north-oriented Osage River tributary valleys. Evidence of former south-oriented flood flow channels can be found along present day drainage divides, especially along drainage divides with a west to east orientation. Figure 4 below provides a detailed map of the Brush Creek-Tanyard Branch drainage divide area south and east of Visita to better illustrate the evidence.

Detailed map of Brush Creek-Tanyard Branch drainage divide area

Figure 4: Detailed map of Brush Creek-Tanyard Branch drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 provides a detailed map of the Brush Creek-Tanyard Creek drainage divide area southeast from Vista, which was seen in less detail in figure 3 above. Vista is the town located near the figure 4 center. Brush Creek flows north from Vista to the figure 4 north center edge and north of the figure 4 map area joins the Osage River. The flooded valley in the figure 4 northeast corner is the Weaubleau Creek valley which is flowing generally in a northwest and north direction to join the Osage River north of the figure 4 map area. High water levels for the Harry S. Truman Reservoir are shown. Tanyard Branch flows in a north-northeast direction across the figure 4 southeast corner and joins Weaubleau Creek east of the figure 4 map area. Note the unnamed southeast-oriented Tanyard Branch tributary in the figure 4 southeast quadrant and how that southeast-oriented tributary valley is linked by a shallow through valley with a northwest-oriented Brush Creek tributary valley. The old railroad line makes use of the through valley. The west and south-southwest oriented streams in the figure 4 southwest quadrant are tributaries to northwest-oriented Coon Creek, which is located south and west of the figure 4 map area. The south-southwest oriented stream is Buckhart Branch and is linked in the section 4 southwest corner by a shallow through valley with a an unnamed northwest-oriented stream, which west of the figure 4 map area flows to the Sac River. A shallow through valley in sections 14 and 15 links the west-oriented Coon Creek tributary valley with the north-oriented Brush Creek valley. All figure 4 through valleys appear to be shallow and are usually defined by only one ten-foot contour line on each side. However, the through valleys are water eroded features and provide evidence of south-oriented flood flow routes that existed prior to the massive flood flow reversal that eroded the present day deep north-oriented valleys.

Coon Creek-Brush Creek drainage divide area

Figure 5: Coon Creek-Brush Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Coon Creek-Brush Creek drainage divide area south of the figure 3 map area (the Brush Creek in figure 5 is a different Brush Creek than the Brush Creek in figures 3 and 4). Humansville is the town located in the figure 5 southeast quadrant. Weaubleau is the town located near the east edge in the figure 5 northeast quadrant and Collins is the town located west of Weaubleau. The north oriented Sac River is meandering in the figure 5 northwest corner. North-northwest oriented Weaubleau Creek can just barely be seen in the figure 5 northeast corner. The South Fork Weaubleau Creek flows in a northwest direction from the figure 5 east center area to Collins and then flows in a north direction along the east side of Collins to the figure 5 north edge. North of the figure 5 map are the South Fork flows to Weaubleau Creek. Coon Creek originates south of Collins and flows in a north direction on the west side of Collins before turning to flow in a northwest direction to the figure 5 north center edge. North of figure 5 Coon Creek joins the north oriented Sac River. Brush Creek is the northwest-oriented stream flowing from near Humansville to the figure 5 south center area where it makes a jog to the southwest before turning to flow in a northwest direction to join the Sac River in the figure 5 northwest quadrant. Green Springs Branch and Price Branch are the two northwest-oriented tributaries flowing to the figure 5 south center edge area to join Brush Creek at or near its elbow of capture (where it turns from flowing in a southwest direction to flowing in a northwest direction). Panther Creek is the northwest, southwest, northwest, and southwest oriented Brush Creek tributary located just north of Humansville and originating near the figure 5 southeast corner. Turkey Creek is the northwest-oriented stream flowing across the figure 5 southwest quadrant and joining the Sac River west of the figure 5 map area. The numerous figure 5 northwest-oriented valley segments probably originated as southeast-oriented flood flow routes to what was once newly reversed flood flow on what is today the north-oriented Pomme de Terre River valley alignment. At that time headward erosion of the deep Osage River valley had not reached the area north of the figure 5 map area and the north-oriented Sac River valley did not exist. Headward erosion of the deep Osage River then beheaded south-oriented flood flow on the Sac River alignment and headward erosion of the deep Sac River valley beheaded and reversed southeast-oriented flood flow routes across the figure 5 map area. The deepest north-south oriented through valley in figure 5 is located between Collins and Humansville and links the north- and northwest-oriented Coon Creek valley with the southwest-oriented Panther Creek valley.

Detailed map of Coon Creek-Panther Creek drainage divide area

Figure 6: Detailed map of Coon Creek-Panther Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 provides a detailed map of the Coon Creek-Panther Creek drainage divide area seen in less detail in figure 5 above. Northwest-oriented Brush Creek is making its jog to the southwest in the figure 6 southwest corner area. South and west of the figure 6 map area Brush Creek resumes its northwest orientation and flows to the north oriented Sac River.  Coon Creek originates in the figure 6 north center area and flows to the figure 6 north center edge. North of the figure 6 map area Coon Creek flows in a northwest direction to the north oriented Sac River. The northwest-oriented stream flowing from the figure 6 east center edge to the figure 6 north edge is the South Fork Weaubleau Creek. North of the figure 6 map area the South Fork Weaubleau Creek flows in a north direction to join north-oriented Weaubleau Creek. Note the north-south oriented through valley in section 30 linking the north oriented Coon Creek valley with the southwest-oriented Panther Creek valley. Unlike through valleys seen in figures 3 and 4 this through valley is deep and easy to recognize. The lowest point where the drainage divide crosses the through valley floor is between 880 and 890 feet. Hills on either side of the through valleys rise to elevations of at least 1000 feet. The through valley represents what was once a south-oriented flood flow channel that has been eroded at least 100 feet deep into the topographic surface on which the south-oriented flood flow originally moved. It is possible flood waters for a time flowed north in the through valley. Headward erosion of the deep north-oriented Sac River valley would have beheaded and reversed flood flow on the Coon Creek alignment before it beheaded and reversed flood flow on the Brush Creek alignment. Reversed flood flow on the Coon Creek alignment probably captured southeast-oriented flood flow from the Brush Creek alignment and some captured flood flow probably moved in a northeast direction on the Panther Creek alignment and then north via the through valley to help erode the deep north- and northwest-oriented Coon Creek valley. Headward erosion of the deep Sac River valley would then have beheaded and reversed flood flow on the Brush Creek alignment with present day drainage routes evolving as flood water drained from the figure 6 map area. Volumes of water involved must have been immense to erode the deep valleys, especially since most deep valleys were eroded during the massive reversal of flood flow that occurred when the Osage River valley beheaded south-oriented flood flow routes.

South Fork Brush Creek-Spring Creek drainage divide area

Figure 7 illustrates the South Fork Brush Creek-Spring Creek drainage divide area located south of the figure 5 map area and includes a thin overlap strip with figure 5. Humansville is the town located in the figure 7 northeast corner. Dunnegan is the much smaller town located south of Humansville. Bearcreek is the small town located near the figure 7 south center edge. Stockton is the town located in the figure 7 southwest corner area. The Stockton Lake Dam is located near Stockton and the north oriented Sac River is located near the figure 7 west edge. The South Fork Brush Creek flows in a northwest and north direction in the figure 7 northeast quadrant to the north edge just west of Humansville. Bear Creek is the northwest and west oriented stream flowing from near Bearcreek to join the Sac River just downstream from the Stockton Lake Dam. The south oriented stream at Dunnegan is Spring Creek which turns to flow in a southwest and northwest direction to join Bear Creek. Note how the south oriented Spring Creek valley is linked by a through valley with the valley of a north oriented South Fork Brush Creek tributary. Also note how the through valley continues south beyond the point where Spring Creek turns to flow in a southwest direction. The through valley continues to the figure 7 south edge and between the figure 7 south edge and the south- and southwest oriented Spring Creek valley segment the north-south oriented through valley is crossed by two different west oriented streams. The southern stream is southwest and northwest-oriented Jump Off Creek and the northern stream is northwest-oriented Campbell Branch. Figure 8 below provides a more detailed map of the Campbell Branch-Jump Off Creek drainage divide area. The north-south oriented through valley probably originated as a south-oriented flood flow channel, but was probably used by north-oriented flood flow during the massive flood flow reversal. The deep Sac River valley was not eroded instantaneously and flood waters still moving south in the figure 7 map area could be captured by reversed flood flow on the north- and northwest-oriented Brush Creek alignment. This captured flood flow could move east, southeast, northeast, and north on the present day Bear Creek-Spring Creek alignment to the reversed flow on the South-Fork Brush Creek-Brush Creek alignment. As seen in figures 5 and 6 the flood flow could then move north to Coon Creek alignment. As the deep Sac River valley eroded south this east and north oriented flood flow route was beheaded and the present day drainage pattern evolved as flood water drained from the region.

Detailed map of Campbell Branch-Jump Off Creek drainage divide area

Figure 8: Detailed map of Campbell Branch-Jump Off Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 provides a detailed map of the Campbell Branch-Jump Off Creek drainage divide area seen in less detail in figure 7 above. Dunnegan is the town located near the figure 8 north center edge. The north-south oriented highway is located in the north-south oriented through valley we have been following in figures 5, 6, and 7 above. Spring Creek flows south in the through valley at Dunnegan, but then turns to flow in a southwest direction to the figure 8 west center edge. West of figure 8 Spring Creek turns to flow in a northwest direction to west-oriented Bear Creek, which then flows to the north-oriented Sac River. Campbell Branch is the northwest-oriented Spring Creek tributary flowing in a northwest in section 16 and then across the through valley floor to join Spring Creek in section 8. Jump Off Creek is the west-oriented stream in sections 23, 22, and 21 which turns to flow in a southwest direction into the through valley and then turns to flow in a northwest direction to join Spring Creek in section 13. Note higher level north-south oriented through valleys linking the northwest-oriented Campbell Branch valley with the west-oriented Jump Off Branch valley in sections 21 and 22 and elsewhere. In fact there is a maze of higher level through valleys that can be identified in the figure 8 map region, which can not be adequately addressed in this essay. The major north-south oriented through valley continues south of the figures 7 and 8 map areas and is again seen in figures 9 and 10 below and is crossed by northwest-oriented Bear Creek before reaching the northwest-oriented Little Sac River valley. As already noted the north-south oriented through valley originated as a south-oriented flood flow channel in what was probably a south-oriented anastomosing channel complex moving flood waters to what were then actively eroding south-oriented White River tributary valleys. Headward erosion of the deep Osage River valley then began to behead and reverse south-oriented flood flow routes in sequence from east to west and newly reversed flood flow routes began to capture flood flow from yet to be beheaded and reversed flood flow further to the west. This captured flood flow moved southeast, east, and northeast to the newly reversed flood flow routes. In other words flood flow movements were complex as seen from the figure 8 evidence.

Bear Creek-Little Sac River drainage divide area

Figure 9: Bear Creek-Little Sac River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Bear Creek-Little Sac River drainage divide area south of the figure 7 map area and includes a thin strip of overlap area with figure 7. Bolivar is the larger town located near the figure 9 east edge. Fair Play is the smaller town in the figure 9 northwest quadrant. Aldrich is the even smaller town located on the highway south of Fair Play near the flooded west-northwest oriented valley. The Little Sac River flows in a northwest direction from the figure 9 south center edge to the flooded west-northwest valley, which is the arm of Stockton Lake flooding the Little Sac River valley. Bear Creek originates south of Bolivar and flows in a northwest direction to the figure 9 north edge near the northwest corner. Fair Play is located in the north-south oriented through valley seen in figures 5, 6, 7, and 8. The highway from Fair Play to Aldrich follows the through valley south to the Little Sac River valley. South of figure 9 the Little Sac River is oriented in a north-northwest direction and may be the southern extension of the north-south oriented through valley. However, because flood flow moved in large-scale and ever-changing anastomosing channel complexes there were probably many diverging and converging channels both as flood waters moved south prior to headward erosion of the deep Osage River valley to the north and later as the massive flood flow reversal gradually evolved and then occurred in response to headward erosion of the deep Osage River valley in the north. Deeper erosion of through valley segments north of the figure 9 map area probably occurred as the flood flow reversal was evolving, which means as the deep Osage River valley was actively eroding headward across the region north of the present day Sac River-Pomme de Terre River drainage divide area. At that time flood waters were flowing north in regions east of the actively eroding Osage River valley and were flowing south in regions west of the actively eroding Osage River valley head. The south-oriented flood flow in west was being captured by the north-oriented flood flow routes to the east and was moving east and then north to the newly eroded Osage River valley and even north and west to actively eroding north-oriented valleys on what were then newly beheaded south-oriented flood flow routes.

Detailed map of Bear Creek-Little Sac River drainage divide area

Figure 10: Detailed map of Bear Creek-Little Sac River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 provides a detailed map of the Bear Creek-Little Sac River drainage divide area seen in less detail in figure 9 above. The flooded northwest-oriented Little Sac River valley is located in the figure 10 southwest quadrant. Bear Creek flows in a west-northwest direction from the figure 10 east center edge area to the figure 10 north edge (west half). Note multiple north-south oriented through valleys crossing the Bear Creek-Little Sac River drainage divide. The north-south oriented highway makes use of through valley in the southeast corner of section 16. The through valley floor where the highway crosses the drainage divide has an elevation of between 1000 and 1010 feet. Hills on either side of the through valley rise to elevations greater than 1100 feet. Another and slightly deeper through valley is located in section 17 southwest corner. The through valley at the drainage divide has an elevation of between 990 and 1000 feet and again hills on either of the trough valley rise to elevations greater than 1100 feet. A somewhat higher level through valley is located along the border between sections 13 and 18 and the floor of that through valley at the drainage divide has an elevation of between 1010 and 1020 feet. An even higher level through valley is seen in section 12 and the floor of that through valley at the drainage divide has an elevation of between 1040 and 1050 feet. Close inspection of the figure 10 map area reveals additional north-south oriented through valleys. The through valleys provide evidence of multiple south-oriented flood flow routes prior to headward erosion of the Bear Creek valley such as in a south-oriented anastomosing channel complex. The Bear Creek valley alignment may have been initiated as south-oriented flood flow from the west began to move southeast and east toward newly reversed flood flow routes moving water to the newly erode and deep Osage River valley. However, the deep northwest-oriented Bear Creek valley was eroded by the reversal of flood flow that occurred when the deep north-oriented Sac River valley beheaded the southeast-oriented flood flow route and caused a local reversal of flood flow along the Bear Creek alignment. The figure 10 evidence also illustrate the magnitude of flood erosion that occurred, although there is no way of determining how much material was removed from the figure 10 map area prior to events that produced the erosion surface defined by the highest figure 10 elevations today.

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 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.