• The purpose of this essay is to use topographic map interpretation methods to explore the Grand River-Missouri River drainage divide area landform origins in Livingston and Carroll 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 essays in the Missouri River drainage basin landform origins research project 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 immense melt water 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 Grand River-Missouri River drainage divide area landform evidence in Livingston and Carroll Counties, Missouri 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.

• Figure 1 provides a location map for the Grand River-Missouri River drainage divide area in Livingston and Carroll Counties, Missouri. The state of Missouri is labeled and Iowa is the state north of Missouri. The south-southwest and south-southeast oriented Mississippi River forms the Iowa and Missouri eastern border and Illinois is the state east of the Mississippi River. Kansas is the state located in the figure 1 southwest corner and the tip of the Nebraska southeast corner can be seen north of Kansas along the figure 1 west edge. The Missouri River flows in a southeast direction along the Missouri western boundary to Kansas City and then turns to flow in an east-northeast direction to Brunswick, Missouri. From Brunswick the Missouri River flows in a southeast direction to Jefferson City (along figure 1 south edge) and then in an east direction to the figure 1 east edge. East of figure 1 the Missouri River joins the south-oriented Mississippi River, which flows to the Gulf of Mexico. The Grand River originates in Iowa just north of the figure 1 map area and flows in a south direction through Diagonal, Iowa (in figure 1 northwest quadrant) and then to Albany, Missouri. Near Albany the Grand River turns to flow in a southeast direction and when north of Brunswick turns to flow in south direction to join the Missouri River near Brunswick. Note how the southeast-oriented Grand River segment has several roughly parallel south-oriented tributaries, including the south-southeast oriented Thompson River. The Grand River-Missouri River drainage divide area in Livingston and Carroll Counties is the region south and west of the Grand River, north of the Missouri River, and east of a north-south line extending from Breckenridge through Braymer to Norborne. The Shoal Creek-Missouri River drainage basin landform origins in Caldwell, Ray, and Carroll Counties essay has described the region immediately to the west.  This essay and essays describing other surrounding drainage divide areas can be found listed under MO grand River and/or MO Missouri River on the sidebar category list.

• Based on topographic map evidence illustrated in this essay and in essays contained in the  Missouri River drainage basin landform origins research project the Grand River-Missouri River drainage divide area in Livingston and Carroll Counties and the entire figure 1 map area was eroded by immense south-oriented glacial melt water floods. Flood waters were derived from a rapidly decaying thick North American ice sheet, which at the time the Missouri River valley and valleys of its figure 1 tributaries (including the Gand River valley) were eroded was located north of the figure 1 map area. The ice sheet probably had been comparable in size to the present day Antarctic Ice sheet, if not larger, and had been located in a deep “hole” The deep “hole” had been created by a combination of crustal warping caused by the ice sheet’s tremendous weight and by deep glacial erosion of the ice sheet’s underlying bedrock surface. The figure 1 map area illustrates a region which was located along the deep “hole’s” southern rim, although evidence of the southern rim was destroyed by deep glacial melt water flood water erosion. Melt water floods flowing from the decaying ice sheet overwhelmed whatever drainage systems once existed and initially flowed in a south direction across the entire figure 1 map area directly to the Gulf of Mexico. Headward erosion of deep southeast-oriented tributary valleys from what was probably an actively eroding Mississippi River valley then began to capture the south-oriented flood flow and to divert the south-oriented flood waters to the Mississippi River valleys. These captures occurred in sequence from south to north. For example in the state of Arkansas, south of the figure 1 map area, the southeast-oriented Arkansas River valley and its tributary valleys captured the south-oriented flood flow before headward erosion of the deep southeast-oriented White River valley and its tributary valleys beheaded flood flow routes to the newly eroded Arkansas River valley and its tributary valleys.

• In the figure 1 map area headward erosion of the deep Missouri River valley (and its east and northeast oriented Osage River tributary valley located south of the figure 1 map area) beheaded flood flow routes to the newly eroded White River valley. As the deep Missouri River valley eroded headward across the state of Missouri south-oriented tributary valleys began to erode headward from the newly eroded Missouri River valley north wall. These south-oriented tributary valleys eroded headward along and across south-oriented flood flow routes, which accounts for the numerous south-oriented Missouri River tributaries seen in figure 1. Headward erosion of the Grand River valley from the actively eroding Missouri River valley head was one of these south-oriented tributary valleys. Unlike some of the other south-oriented tributary valleys, once north of the actively Missouri River valley the Grand River valley eroded headward toward the northwest to capture multiple south-oriented flood flow routes which were moving flood waters to the newly eroded east-oriented Missouri River valley. Headward erosion of the Shoal Creek valley, which is an east-oriented Grand River tributary valley joining the Grand River south of Chillicothe, Missouri first captured the south-oriented flood flow and diverted the flood waters to the newly eroded Grand River valley. Headward erosion of the southeast-oriented Grand River valley subsequently beheaded south-oriented flood flow routes to the newly eroded Shoal Creek valley. Later, headward erosion of the east-oriented Chariton River headwaters valley (which is seen in figure 1) and then of southeast-oriented Des Moines River valley (from the Missouri River valley at the Iowa-Missouri state line) and its tributary valleys (north of figure 1 and not seen) beheaded south-oriented flood flow routes to the actively eroding Grand River valley and its south-oriented tributary valleys.

• Figure 2 provides a more detailed location map for the Grand River-Missouri River drainage divide area in Livingston and Carroll Counties, Missouri. County names and boundaries are shown. The Missouri River flows in an east-northeast direction from Kansas City (near the figure 2 southwest corner) along the Clay, Ray, and Carroll County southern borders and then turns to flow in a southeast direction along the Chariton County southwest border and then in a south direction to the figure 2 south edge. The major Missouri River tributary in Carroll County (besides the Grand River) is Wakenda Creek, which originates in northeast Ray County and flows in a southeast direction to the north edge of the Missouri River valley near Norborne in western Carroll County and then which flows along the Missouri River valley north edge for a considerable distance before joining the Missouri River in eastern Carroll County. Wakenda Creek has several south oriented tributaries, although Turkey Creek in western Carroll County is the only labeled tributary in figure 2. The situation where Wakenda Creek flows along the Missouri River north edge and the Missouri River channel is located near the valley’s south margin probably reflects the inability of south and southeast oriented flood flow moving into the newly eroded Missouri River valley to fully merge with the large flood flow volumes moving eastward from further to the west. Similar patterns can be seen on other rivers, especially the Platte River in Nebraska (see Loup River-Platte River drainage divide area landform origins between Kearney and Columbus, Nebraska essay under NB Platte River on sidebar category list).  The Grand River is the south-southeast oriented river forming the Carroll-Chariton County border and flows in a southeast direction from the figure 2 north edge across Daviess and Livingston Counties to the Chariton County northeast corner. Major Grand River tributaries in Livingston and Carroll County are Shoal Creek and Big Creek. Shoal Creek originates in northeast Clinton County and flows in a generally east direction across Caldwell County. After making a jog in a south direction along the Caldwell-Livingston County border Shoal Creek then flows in a northeast direction to join the Grand River just south of Chillicothe. Big Creek originates in northern Carroll County and flows in a southeast, east, south-southeast, and east-northeast direction to join the Grand River in the Carroll County southeast corner area. A named Big Creek tributary is Bridge Creek, which originates in southern Livingston County and which flows for a short distance in a north direction before turning to flow in a south direction to join Big Creek near Tina in Carroll County. The parallel Big Creek channels shown south of Tina on figure 2 probably reflect new and old Big Creek channels. The sequence of drainage history events described by figure 2 drainage patterns is the Missouri River valley eroded headward across the Carroll County southern border to capture southeast and south-oriented flood flow while the Grand River valley was eroding headward along the Carroll-Chariton County border along a major south-oriented flood flow route. When reaching southeast Livingston County the Grand River valley then began to erode headward across south-oriented flood flow routes beheading flood flow routes to the newly eroded Missouri River valley, with the Shoal Creek valley eroding  across the southeast-oriented flood flow. Grand River valley headward erosion then beheaded flood flow routes to the newly eroded Shoal Creek valley.

• Figure 3 uses a reduced size topographic map to illustrate the Grand River-Shoal Creek drainage divide area in Livingston County. Chillicothe is the larger town in the figure 3 northeast corner. Breckenridge is the largest town located in the figure 3 northwest quadrant. The Grand River flows in an east-southeast direction from the figure 3 north edge to the east edge (in figure 3 north half). Note how the Grand River has several north oriented tributaries from the south. Big Branch is the north oriented tributary located near Breckenridge. Ludlow is a small town located just north of the figure 3 south center edge. Shoal Creek flows in an east and northeast direction from the figure 3 west edge (south half) and then turns to flow in a south and an east direction between Ludlow and the figure 3 south edge before turning to flow in a northeast direction to join the Grand River near the figure 3 east edge. Note the north-oriented Shoal Creek tributaries from the south and also how Shoal Creek has numerous south and southeast oriented tributaries from the north. In addition note how headwaters of south oriented Shoal Creek tributaries are aligned with headwaters of north-oriented Grand River tributaries. At some locations shallow through valleys can be seen linking the north- and south oriented tributary valleys. The shallow through valleys are usually defined by a single ten-meter contour line on each side and are better seen on more detailed topographic maps. The north-oriented barbed tributaries to the south oriented Grand River are located in valleys eroded by reversals of flood flow on north ends of beheaded south oriented flood flow channels. The Grand River-Shoal Creek drainage divide area illustrates how this process occurred. Headward erosion of the deep Shoal Creek valley first captured south- and southeast-oriented flood flow, which had been moving across an upland surface at least as high as the highest figure 3 elevations today. The south-oriented Shoal Creek valley segment was eroded headward along one south-oriented flood flow channel while northeast-oriented valley segments were eroded across multiple south- and southeast-oriented flood flow channels. South-oriented tributary valleys eroded headward from the newly eroded Shoal Creek north valley along south-oriented flood flow routes. Grand River valley headward erosion then beheaded the south-oriented flood flow channels to the actively eroding Shoal Creek tributary valleys in sequence from east to west. Flood waters on north ends of the beheaded flood flow channels reversed flow direction to erode the north-oriented Grand River tributary valleys.

• Figure 4 provides a detailed topographic map of the Big Branch-Shoal Creek drainage divide area seen in less detail in figure 3 above. The labeled north-south boundary between Range 26 West and Range 25 West located in the figure 4 east half is also the boundary between Caldwell County (west) and Livingston County (east). The north-oriented stream originating in the section 11 southeast quadrant and flowing through section 2 to the figure 4 north center edge is Big Branch, which north of the figure 4 map area turns to flow in a northeast direction to join the southeast-oriented Grand River. Note how Big Branch has northwest-oriented tributaries from the east and northeast-oriented tributaries from the west. The east and south oriented stream originating in the section 11 southwest quadrant and flowing in a south direction near the section 14 east border to the figure 4 south edge is a tributary to southeast-oriented Panther Creek, although its joins Panther Creek along the north edge of the Shoal Creek valley. Since the stream flows independently to the Shoal Creek valley north edge it is here considered to be located in a valley which eroded headward from the Shoal Creek valley and hence is described as a Shoal Creek tributary. Note how the south-oriented Shoal Creek tributary valley is linked by a through valley in the section 11 southeast quadrant with the north-oriented Big Branch valley. The map contour interval is 4 meters and the through valley floor elevation is between 260 and 264 meters. Elevations in the section 12 southeast quadrant rise to at least 284 meters and elevations in the Breckenridge city limits also rise to more than 284 meters. In other words the through valley is at least 20 meters deep and provides evidence of a south-oriented flood flow channel which existed prior to headward erosion of the deep Grand River valley (north of the figure 4 map area). At the time the through valley was eroded flood waters were flowing to the actively south-oriented Shoal Creek tributary valley, which had eroded headward from what was then the newly eroded Shoal Creek valley. Headward erosion of the deep southeast-oriented Grand River valley and its northeast-oriented Big Branch tributary valley beheaded the south-oriented flood flow channel. Flood waters on north ends of the beheaded diverging south-oriented flood flow routes reversed flow direction to erode the north-oriented Big Branch valley segment and its tributary valleys.

• Figure 5 uses a reduced size topographic map to illustrate Grand River-Bridge Creek drainage divide area south and east of the figure 3 map area. Hale is the town located in the figure 5 southeast quadrant and Avalon is the smaller town located near the figure 5 center. Utica is the town straddling the figure 5 west edge near the northwest corner. The Grand River flows in an east-southeast direction across much of the figure 5 north half and then flows in a south direction near the figure 5 east edge. Shoal Creek is the northeast-oriented Grand River tributary in the northwest corner area. Bedford is a town just south of the Grand River in the figure 5 northeast quadrant. Note north oriented Grand River tributaries from the south. Named tributaries from east to west are northeast-oriented Campbell Creek, northeast-oriented Johnson Creek,  north and northwest oriented Wolf Grove Creek, north oriented Mound Creek, and north-oriented Brush Creek.  These barbed tributaries, especially the north- and northwest-oriented tributaries are flowing in valleys eroded by reversals of flood flow on north ends of south-oriented flood flow routes beheaded by Grand River valley headward erosion. Note how these north-oriented Grand River tributaries are linked to south-oriented streams flowing to the figure 5 south edge. For example, south and west of Avalon are east- and northeast-oriented headwaters of south-southeast oriented Bridge Creek, which flows to the figure 5 south edge (east of center).  South of the figure 5 map area Bridge Creek turns to flow in a south-southwest direction to join south-southeast, east, and northeast oriented Big Creek, which flows to the Grand River a short distance upstream from where the Grand River joins the Missouri River. Buris Creek is a south-oriented Bridge Creek tributary located between Avalon and Hale. Note how the Buris Creek headwaters are linked by a through valley with north-northeast oriented Campbell Creek headwaters valley. The through valley provides evidence of a south-oriented flood flow channel which was beheaded and reversed by Grand River valley headward erosion. West of the south-oriented Bridge Creek segment is southeast-oriented Mound Creek, which flows to the figure 5 south center edge and then joins Bridge Creek south of the figure 5 map area. This south-oriented Mound Creek valley is linked by through valleys with the north-oriented Mound Creek, which flows to the Grand River. Figure 6 below provides a detailed map of the Mound Creek-Mound Creek drainage divide area to better illustrate the somewhat more complicated through valley relationship in that region.

• Figure 6 provides a detailed topographic map of the north-oriented Mound Creek-south-oriented Mound Creek drainage divide area seen in less detail in figure 5 above. Blue Mound is the town in the northwest quadrant. The north-oriented Mound Creek originates in section 1 and flows in a northeast direction across the section 36 southeast quadrant, the section 31 northwest quadrant, and the section 30 southeast quadrant to the figure 6 north center edge. North of the figure 6 map area north-oriented Mound Creek as seen in figure 5 flows to the east-southeast oriented Grand River. Note how the north-oriented Mound Creek valley has southeast-oriented tributaries in section 36 and section 29. The southeast-oriented barbed tributaries provide evidence of what were once southeast-oriented flood flow channels captured by headward erosion of the deep northeast-oriented north-oriented Mound Creek headwaters valley. The south-oriented Mound Creek originates in the section 1 east half and flows in a northeast direction into section 6 where it turns to flow in a southeast and east direction into section 5. Once in section 5 the stream flows in a northeast direction to the northeast corner and then flows in a southeast direction to the figure 6 east edge (just north of southeast corner). South and east of figure 6 the south-oriented Mound Creek flows in a southeast direction to Bridge Creek with water eventually reaching the Grand River near where the Grand River enters the Missouri River. Note how the north-oriented Mound Creek valley is linked to the south-oriented Mound Creek valley by multiple through valleys. The deepest through valley is located in the section 31 southeast quadrant and has a valley floor elevation of between 850 and 860 feet (the map contour interval is 10-feet). Elevations north and east of the through valley rise to more than 890 feet while to the south and west elevations rise to more than 910 feet. The through valley links a northwest-oriented tributary valley to the north-oriented Mound Creek with a southeast-oriented tributary valley to the south-oriented Mound Creek. Another well-defined through valley is located in the section 6 northwest quadrant and has a valley floor elevation of between 870 and 880 feet. Elevations directly to the northeast rise to more than 910 feet while elevations to the southwest rise to more than 960 feet. A shallower through valley can be seen in the section 32 northwest quadrant and links a northwest-oriented tributary valley with a southeast-oriented tributary valley. The through valleys provide evidence of southeast-oriented flood flow channels to what was once the actively eroding southeast-oriented Mound Creek valley. These southeast-oriented flood flow channels were beheaded by headward erosion of the deep north-oriented Mound Creek valley, which was eroded headward by flood waters which were reversed when the deep Grand River valley beheaded south-oriented flood flow routes to the figure 6 map area.

• Figure 7 uses a reduced size topographic map to illustrate the Cottonwood Creek-Tater Hill Creek drainage divide area located south and west of the figure 5 map area and includes overlap areas with figure 5. Blue Mound is the small town near the quarry (marked “Pits”) in the figure 7 north center area. Tina is the town south of the figure 7 east center area. Shoal Creek flows in an east-southeast and northeast direction near the figure 7 northwest quadrant north edge. The north-oriented Shoal Creek tributary in the figure 7 northwest quadrant is Cottonwood Creek. Note how Cottonwood Creek has northwest and west oriented tributaries from the east. The south-southeast and south oriented stream in the figure 7 southwest quadrant is Turkey Creek. South of the figure 7 map area Turkey Creek flows in a south direction to join east-oriented Wakenda Creek, which is flowing along the north edge of the east-oriented Missouri River valley. Note the through valley labeled as Low Gap linking the north-oriented Cottonwood Creek valley with the south-oriented Turkey Creek valley. There is nothing subtle about Low Gap. The map contour interval is 10 meters and the Low Gap floor elevation is between 240 and 250 meters. Elevations east of Low Gap rise to at least 300 meters and elevations west of Low Gap rise to more than 280 meters (with one small spot appearing to be 290 meters). Low Gap provides evidence of a major south-oriented flood flow channel to what was then the newly eroded Missouri River valley. At that time the deep Shoal Creek valley north of the figure 7 map area (and Grand River still further north) had not been eroded. Before the deep Low Gap flood flow channel was eroded flood waters flowed across a surface as high as the highest figure 7 elevations today and was flowing in a southeast direction to the south-oriented Bridge Creek and Big Creek valleys located in the figure 7 east half. The south-southwest oriented stream flowing near Tina is Bridge Creek and is joined by southeast-oriented Mound Creek near Tina. Just downstream from Tina Bridge Creek joins east-northeast oriented Big Creek, which then turns to flow in a south-southeast direction to the figure 7 south edge (near southeast corner). Big Creek originates near Mandeville in the figure 7 south center area and flows in a south and east direction before turning to flow in an east-northeast direction to join Bridge Creek. The labeled tributary north of Big Creek is east-southeast and southeast oriented Tater Hill Creek, which is linked by shallow through valleys with northwest-oriented Cottonwood Creek tributaries. Valley orientations and shallow through valleys provide evidence of southeast-oriented flood flow routes to the actively eroding Tater Hill Creek valley prior to headward erosion of the much deeper south-oriented Low Gap flood flow channel. Figure 8 below provides a detailed topographic map to better illustrate the shallow through valleys.

• Figure 8 provides a detailed topographic map of the Bunch Hollow-Tater Hill Creek drainage divide area seen in less detail in figure 7 above. Bunch Hollow is the northwest-oriented valley draining to the figure 8 northwest corner. Bunch Hollow and other west-oriented valleys draining to the figure 8 west edge drain to northwest-oriented Cottonwood Creek tributaries (see figure 7). All south-oriented valleys draining to the figure 8 south edge drain to east-oriented Tater Hill Creek, which is located just south of the figure 8 map area. There are no deep through valleys in the figure 8 map area similar to the Low Gap through valley located a short distance to west. Instead the Cottonwood Creek-Tater Hill Creek drainage divide appears to be a fairly continuous ridge extending in south-southwest direction from section 10 across the section 15 northwest corner and the section 16 southeast corner into section 21 and then to the figure 8 south edge. However, study of that drainage divide reveals the presence of former southeast-oriented flood flow channels notched into the ridge. The deepest channel floor is located in the section 15 northwest corner where the through valley floor elevation is between 950 and 960 feet (the map contour interval is ten feet). Elevations in section 10 rise to more than 970 feet (and in section 3 north of the figure 8 map area to more than 990 feet).  Elevations in section 21 also rise to more than 990 feet. Other more subtle channels can also be seen. For example in section 21 there is a subtle northwest-southeast oriented through valley defined by a single contour line on each side and located at the top of the highest figure 8 hill shown. These through valleys provide evidence southeast-oriented flood flow once moved across the entire figure 8 map area, which has the highest elevations shown on the figure 7 map. The figures 7 and 8 maps provide evidence flood waters stripped much of the Grand River-Missouri River drainage divide area of at least 50 meters of surface material between the time flood waters flowed across the figure 8 drainage divide and the time headward erosion of the deep Grand River-Shoal Creek valley beheaded and reversed flood flow to erode the north-oriented Cottonwood Creek valley seen in figure 7. And, the figure 8 map evidence shows flood waters flowed across the highest elevations present today, meaning there are no markers to determine how much material was stripped from the region prior to time flood waters flowed across the figure 8 drainage divide.

• Figure 9 uses a reduced size topographic map to illustrate the Big Creek-Shootman Creek drainage divide area south and east of the figure 7 map area and includes overlap areas with figure 7. Bogard is the town located a short distance west of the figure 9 center. The east-oriented Missouri River valley is located a short distance south of the figure 9 south edge. Mandeville Lake in the figure 9 northwest corner is located in a west-oriented valley which drains to a northwest-oriented Cottonwood Creek tributary, with Cottonwood Creek draining in a north direction to Shoal Creek (see figure 7). Big Creek originates a short distance east of Mandeville Lake and flows in a south and then southeast direction before flowing in an east and east-northeast direction to the figure 9 north edge. The southeast-oriented Big Creek tributary flowing from the figure 9 north center edge is Tater Hill Creek and south-oriented Bridge Creek joins Big Creek just north of where Big Creek turns to flow in a south-southeast direction to the figure 9 southeast quadrant. In the figure 9 southeast quadrant Big Creek turns to flow in an east direction and joins the south-southeast oriented Grand River east of the figure 9 map area. Note north-oriented Big Creek tributaries in the figure 9 southeast quadrant. The north-oriented tributary valleys were eroded by reversals of flood flow on north ends of beheaded south-oriented flood flow routes to what was then the actively eroding Missouri River valley located to the south. Shootman Creek originates in the figure 9 center region and flows in a southeast direction to join Big Creek near where the railroad line in the southeast quadrant crosses Big Creek. Note how the southeast-oriented Shootman Creek headwaters are linked by a well-defined through valley with the east-northeast oriented Big Creek valley to the northwest (a north-oriented railroad line is located in the through valley). The through valley floor elevation is between 240 and 250 meters and elevations on either side rise to more than 260 meters (the map contour interval is 10-meters). South-oriented stream west of Shootman Creek, which flow to figure 9 south edge, are Wakenda Creek tributaries and flow to east-oriented Wakenda Creek, which flows along the north edge of the east-oriented Missouri River valley. McCroskie Creek is the south-southwest and southwest oriented stream flowing to the figure 9 southwest corner. Note how the McCroskie Creek headwaters are linked by a through valley with the east-northeast oriented Big Creek valley north of Bogard. The through valley floor elevation is between 250 and 260 meters. Mound Bogard is located east of the through valley and rises to an elevation of almost 290 meters. An unlabeled mound northwest of the through valley is at least 280 meters high. The through valleys suggests the east-northeast-oriented Big Creek valley segment originated as a west-southwest channel, which captured southeast-oriented flood flow and diverted the flood waters to the actively eroding Missouri River valley head. Headward erosion of the deep Big Creek valley from the actively eroding Grand River valley then captured the east-northeast end of the former west-southwest oriented flood flow channel to create the elbow of capture seen near the figure 9 north edge.

• Figure 10 provides a detailed map of the Big Creek-Shootman Creek drainage divide area seen in less detail in the figure 9 map area. Bogard is the town located near the figure 10 south center edge. Big Creek flows across section 14 (in the figure 10 northwest quadrant) and then turns in section 13 to flow in an east-northeast direction across section 18 to the figure 10 north edge. Note the north-northeast oriented Big Creek tributary flowing through section 19 to join Big Creek just north of the figure 10 north edge. Shootman Creek originates in section 21 (near east edge) and flows in a south-southeast direction into section 28 and to the figure 10 east edge. The southeast-oriented stream in the section 29 northeast quadrant and flowing across the section 28 southwest corner to the figure 10 south edge (near southeast corner) is a Shootman Creek tributary. Note how in section 20 a southeast-oriented Shootman Creek tributary valley is linked by a through valley to a northwest-oriented tributary valley to the previously mentioned north-northeast oriented Big Creek tributary valley. The through valley floor elevation is between 810 and 820 feet (the map contour interval is 10 feet). Mound Bogard to the west rises to more than 950 feet while elevations in the section 20 northeast quadrant rise to at least 860 feet. The south-oriented stream originating directly south of Mound Bogard in section 25 is McGill Creek, which south of figure 10 flows directly in a south-southwest direction to Wakenda Creek, which is flowing along the north edge of the Missouri River valley. Note through valleys immediately east of Mound Bogard in the section 25 northeast quadrant linking the south-oriented McGill Creek valley with north-oriented Big Creek tributary valleys. The through valley floor elevations are again between 810 and 820 feet. The south-southwest oriented stream originating in section 26 west of Mound Bogard is a McCroskie Creek tributary, and south of the figure 10 map area McCroskie Creek flows in a south-southwest direction to join Wakenda Creek, which is flowing along the north edge of the Missouri River valley. Note the through valleys in the section 25 northwest corner and the section 23 southeast corner linking the McCroskie Creek tributary valley with north-oriented Big Creek tributary valleys. The through valley floor elevations are between 840 and 850 feet, but as already mentioned Mound Bogard in section 25 rises to at least 950 feet while an unnamed mound in the section 23 northeast quadrant rises to at least 940 feet. The through valleys provide evidence of multiple south-oriented flood flow channels, which were beheaded and captured so as to create the east-northeast oriented Big Creek valley segment, which had been beheaded and reversed by headward erosion of the Big Creek valley from the newly eroded Grand River valley 9 see figures 2 and 9).

Additional information and sources of maps studied