• The purpose of this essay is to use topographic map interpretation methods to explore the Shoal Creek-Missouri River drainage divide area landform origins in Caldwell, Ray, 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 Shoal Creek-Missouri River drainage divide area landform evidence in Caldwell, Ray, and Carroll Counties, Missouri will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see menu at top of page for paradigm related essay). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

• Figure 1 is a location map for the Shoal Creek-Missouri River drainage divide area in Caldwell, Ray, and Carroll Counties, Missouri. The state of Missouri occupies much of the figure 1 map area and is labeled. Illinois is the state east of the south and south-southeast Mississippi River, which forms the Missouri-Illinois border. Kansas is the state west of Missouri except in the figure 1 northwest corner where Nebraska is west of the Missouri northwest corner. The Missouri River flows in a south-southeast direction from the figure 1 northwest corner to Kansas City and then turns to flow in an east-northeast direction to Brunswick. At Brunswick the Missouri River turns to flow in a southeast direction to Jefferson City and then turns to flow in a generally east direction to the figure 1 east edge and then to join the south-oriented Mississippi River. Shoal Creek is an east-oriented stream located north of the east-northeast oriented Missouri River segment between Kansas City and Brunswick and is a tributary to the southeast and south oriented Grand River, which joins the Missouri River near Brunswick. A close look at figure 1 reveals Shoal Creek begins as a north-northeast oriented stream near Lathrop and then near Cameron turns to flow in more of an east direction to join the Grand River south of Chillicothe. The study region investigated in Caldwell, Ray, and Carroll Counties is located between east-oriented Shoal Creek and the east-northeast oriented Missouri River to the south. Figure 1 shows two southeast-oriented Missouri River tributaries and no Shoal Creek tributaries in the study region, so more detailed maps are needed to determine the drainage divide history.

• Based on evidence illustrated and described in this essay and also in other essays included in the Missouri River drainage basin landform origins research project the Shoal Creek-Missouri River drainage divide area was eroded by immense south-oriented floods. Flood waters were derived from a rapidly melting thick North American ice sheet located north of the study region. At the time present day Shoal Creek-Missouri River drainage divide area landforms evolved, the decaying ice sheet’s southern margin was located in southeast South Dakota and southwest Minnesota and melt water floods were flowing in a south direction across the entire figure 1 map area. Whatever drainage systems existed at that time were overwhelmed by the gigantic south-oriented melt water floods and were completely destroyed by the intense flood water erosion. In other words, no preglacial landforms or drainage routes exist. The ice sheet had previously been larger, and had probably been as large if not larger than the modern-day Antarctic Ice Sheet. The ice sheet had been located in a deep “hole” and the figure 1 map area was located on the deep “hole’s” southern rim. The deep “hole” had been created by deep glacial erosion and also by crustal warping caused by the ice sheet’s great weight. The deep “hole’s” southern rim area was deeply eroded by melt water flood erosion. No markers exist to permit calculations of how much material was stripped from the figure 1 map area prior to headward erosion of present day river and tributary valleys, although it is possible hundreds of meters of material were removed. Melt water flood erosion and deposition has also probably so confused evidence the ice sheet’s maximum southern margin may never be determined.

• Present day valleys eroded headward into the figure 1 map area from the actively eroding Mississippi River valley to capture the immense south-oriented floods and to divert the flood waters to the south-oriented Mississippi River valley. South of the figure 1 map area in the state of Arkansas the southeast-oriented Arkansas River valley eroded headward to capture south-oriented flood flow prior to headward erosion of the southeast-oriented White River valley. Headward erosion of the White River valley captured south-oriented flood flow prior to headward erosion of the deep east oriented Missouri River valley in Missouri to the north. In Missouri headward erosion of the east and northeast-oriented Osage River valley from the Jefferson City area was slightly in advance of headward erosion of the east-northeast and southeast oriented Missouri River valley segment to the north. And, headward erosion of the Grand River-Shoal Creek valley occurred after headward erosion of the east-northeast Missouri River valley segment to the south. Evidence supporting this flood origin interpretation is found on more detailed maps and especially on detailed topographic maps. Evidence includes alignments of north-oriented Shoal Creek tributaries with south-oriented Missouri River tributaries and shallow north-south oriented through valleys eroded across the present day west to east oriented Shoal Creek-Missouri River drainage divide, which suggest the presence of multiple south-oriented flood flow channels, such as might be found in a large-scale anastomosing channel complex. Additional evidence includes numerous elbows of capture and barbed tributaries providing evidence of flood flow channel captures and reversals when beheaded by headward erosion of actively eroding deep valleys.

• Figure 2 is a more detailed location map for the Shoal Creek-Missouri River drainage divide area in Caldwell, Ray, and Carroll Counties, Missouri. County names and boundaries are shown. The Missouri River meanders in an east-northeast direction from Kansas City (near southwest corner) towards Brunswick (near Carroll County southeast corner) and forms the Clay, Ray, and Carroll County southern border. Shoal Creek originates in eastern Clinton County, just north of Lathrop, and flows in a north-northeast direction into Caldwell County where it turns to flow in more of an east direction to eventually join the southeast oriented Grand River just south of Chillicothe in Livingston County. From the Chillicothe area the Grand River flows to the Linn County southwest corner and then forms the border between Carroll County (to the west) and Chariton County (to the east) before joining the Missouri River just south of Brunswick. Labeled figure 2 Shoal Creek tributaries in western Caldwell County are northeast oriented Goose Creek, north-northeast and east oriented Log Creek and in eastern Caldwell County and northeast Ray County the labeled Shoal Creek tributary is southeast, northeast, and east-oriented Mud Creek, which joins Shoal Creek in the Livingston County southwest corner. Labeled study region Missouri River tributaries include southeast-oriented Crooked River and its south-southeast oriented East Fork tributary and southeast and east-southeast oriented Wakenda Creek and its southeast-oriented West Fork and south-southeast oriented Turkey Creek tributaries. Note how Missouri River tributaries tend to be oriented in southeast directions especially in their headwaters regions. The southeast-oriented Missouri River tributaries developed as deep valleys eroded headward from the newly eroded Missouri River valley along and across southeast and south-southeast oriented flood flow routes. Also note the southeast-oriented headwaters and tributary flowing to the north-northeast oriented Mud Creek valley. The elbows of capture developed as the deep north-northeast Mud Creek valley eroded headward across southeast-oriented flood flow routes. While perhaps not obvious from the figure 2 evidence the north-northeast oriented Shoal Creek tributary valleys eroded headward across southeast and south-southeast oriented flood flow channels to capture flood flow and divert flood waters to the actively eroding Shoal Creek valley. Evidence for the flood flow channels and capture events is better seen on topographic maps, a few samples of which are illustrated and described in the discussion below.

• Figure 3 illustrates the Shoal Creek-Crooked River drainage divide area near Lathrop, Missouri. Lathrop is the larger town near the figure 3 south edge, Wexford is the much smaller town near the figure 3 southwest corner. Wallace State Park is labeled in the figure 3 northeast quadrant and the north-south oriented Clinton-Caldwell County border is located along the Wallace State Park eastern boundary. The Little Platte River flows in a south and south-southwest direction near the figure 3 west edge and south and west of the figure 3 map area turns to flow in a west direction to join the south-oriented Platte River, which flows to the southeast-oriented Missouri River upstream from Kansas City. Note northwest and west-northwest oriented tributaries to the south-southwest oriented Little Platte River in the figure 3 southwest quadrant. Shoal Creek begins near the figure 3 south edge, just east of Lathrop, and flows in a northwest direction toward Lathrop before turning to flow in a north and north-northeast direction to the figure 3 north edge (just north of Wallace State Park). Deer Creek is the north-oriented Shoal Creek tributary flowing through Wallace State Park and Plum Creek is the north-northeast oriented Shoal Creek tributary located east of Deer Creek. Goose Creek is the northeast and north-northeast oriented tributary flowing to the figure 3 northeast corner. Deer Creek, Plum Creek, and Goose Creek join Shoal Creek north and/or northeast of the figure 3 map area. Note how Shoal Creek, Deer Creek, Plum Creek, and Goose Creek have at least some north- and northwest-oriented tributaries from the south and east and at least some southeast-oriented tributaries from the north and west. The northeast and southeast oriented stream near the south edge of the figure 3 southeast quadrant is the Crooked River, which south and east of the figure 3 map area flows in a southeast direction to join the east-oriented Missouri River. East-southeast and south oriented Stevenson Creek and south-oriented Spring Branch are the two labeled Crooked River tributaries seen in figure 3. Note how the south-oriented Spring Branch valley is linked by a shallow through valley with a north-oriented Goose Creek tributary valley and how a south-oriented Stevenson Creek tributary valley is linked by a shallow through valley with the north-northeast oriented Plum Creek valley. The through valleys provide evidence of south-oriented flood flow channels to what was at one time the actively eroding Crooked River valley. Headward erosion of the deep east-oriented Shoal Creek valley beheaded the south-oriented flood flow routes and flood waters on north ends of the beheaded flood flow routes reversed flow direction to erode the north-oriented valleys. North and northwest oriented tributary valleys originated as diverging south-oriented flood flow channels, which were reversed when flood waters were reversed to erode the north-oriented valleys, or in the case of the Little Platte River, when Little Platte River valley headward erosion beheaded the south-oriented flood flow.

• Figure 4 provides a detailed topographic map of the Goose Creek-Spring Branch drainage divide area seen in less detail in figure 3 above. The Clinton-Caldwell County line is located near the figure 4 west edge. North-oriented streams flowing to the north edge of the figure 4 northwest quadrant are headwaters of Goose Creek tributaries with the Goose Creek headwaters originating in the section 8 northeast quadrant and flowing through the east half of section 5. North of the figure 5 map area Goose Creek flows in a northeast direction to join east-oriented Shoal Creek. The north and east-northeast drainage system in the figure 4 east half and flowing to the figure 4 east edge (south of the northeast corner) is Log Creek, which will be seen again in figure 5 below. Originating in the section 8 southeast quadrant is south-oriented Spring Branch, which flows through the section 17 east half and into section 20 before reaching the figure 4 south edge. South of figure 3 Spring Branch flows to the southeast-oriented Crooked River, which then flows to the Missouri River. Note how in the section 8 center there is a shallow through valley linking the north-oriented Goose Creek valley with the south-oriented Spring Branch valley. The section 8 through valley is defined by one 4-meter contour line on each side and is a subtle feature. Slightly deeper through valleys can be found linking north-oriented Goose Creek tributary valleys with south-oriented Crooked Creek tributary valleys. For example in the section 9 southwest quadrant a through valley is defined by two 4-meter contour lines on each side and another through valley is defined by one contour line on each side. In the south half of section 7 there are two through valleys defined locally by one contour line on each side, but by going to the east and west elevations rise even higher to define a much broader through valley. In section 22 shallow through valleys can be seen linking north-oriented Log Creek tributary valleys with south-oriented Crooked River tributary valleys. The through valleys seen in the figure 4 map area are subtle, but they exist and provide evidence of multiple south-oriented flood flow channels such as might be found in a south-oriented anastomosing channel complex. At the time flood flow channels were eroded the deep north-oriented valleys had not been eroded and flood waters were flowing on surface at least as high as the Shoal Creek-Crooked River drainage divide today. Headward erosion of the deep Shoal Creek valley beheaded and reversed 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 erode north-oriented valleys. Because flood flow routes were beheaded and reversed in sequence, from east to west and one at a time, flood waters in a newly beheaded and reversed flood channel could capture flood waters from yet to be beheaded flood flow routes further to the west. Such captures of flood water provided large water volumes required to erode north-oriented valleys.

• Figure 5 illustrates the Shoal Creek-Log Creek drainage divide area north and east of the figure 3 map area. Shoal Creek flows in an east and east-southeast direction from the figure 5 northwest corner to Bonanza (a place-name in the figure 5 northeast quadrant) and then turns to flow in a northeast direction to the figure 5 east edge (near northeast corner). Plum Creek is the north-northeast oriented tributary flowing from the figure 5 west center edge to join Shoal Creek at the figure 5 north edge (near northwest corner). Goose Creek is the north-northeast and northeast oriented tributary flowing from the figure 5 west edge (south half) to join Shoal Creek in the figure 5 north center area. Log Creek originates north of the word ROCKFORD in the southwest quadrant and flows in an east and northeast direction to Kingston and then in an east-southeast and northeast direction to join Shoal Creek near Bonanza. Tub Creek is a northeast and east-southeast Log Creek tributary originating near the small town of Mirabile (located just south of figure 5 west center area). Polo is a town straddling the figure 5 south edge (south of Kingston) and Long Creek is the north-northeast oriented Log Creek tributary just west and north of Polo, which joins Log Creek a short distance downstream from Kingston. East of Polo are headwaters of north-northeast oriented Brush Creek, which joins Log Creek just south of Bonanza. Crabapple Creek is the north-oriented Shoal Creek tributary near the figure 5 east edge. Cowgill is the town located in the southeast corner. Spring Branch is the south oriented stream near the figure 5 southwest corner and headwaters of the south-oriented East Fork Crooked River are seen between Polo and Cowgill along the figure 5 south edge. Spring Branch and the East Fork Crooked River flow to the southeast-oriented Crooked River, which flows to the Missouri River. Note in the region between Polo and Cowgill how the north-oriented Brush Creek valley is linked by shallow through valleys with the south-oriented East Fork Crooked River valley (a through valley also links the north-oriented Crabapple Creek valley with the south-oriented East Fork valley, although the through valley east side is not visible in figure 5). A number of other shallow through valleys can be on the figure 5 map, although generally through valleys in this region are shallow and better seen on more detailed topographic maps. Figure 6 below provides a detailed topographic map of the Shoal Creek-Goose Creek drainage divide area located in the figure 5 northwest quadrant.

• Figure 6 provides a detailed topographic map of the Shoal Creek-Goose Creek drainage divide area seen in less detail in figure 5 above. Far West is place-name located near the 6 center and Kerr is a small community located north of Far West. Shoal Creek flows in an east-southeast direction from the figure 6 north center edge area to the figure 6 east edge (north half). Goose Creek flows in a northeast and east direction from the figure 6 south center edge area to the section 12, 13, 7, and 8 corner and then in a southeast direction to the figure 6 east edge. A short distance east of the figure 6 map area Goose Creek joins Shoal Creek. Willow Branch originates in section 16 and flows in a northeast direction into section 10 and then in a north direction to join Shoal Creek. The north-oriented stream seen in the figure 6 northwest corner is Plum Creek. Note shallow through valleys in the figure 6 southwest quadrant linking north-oriented Willow Branch tributary valleys with south and southeast oriented tributary valleys to an east-oriented Goose Creek valley (located along the figure 6 south edge). Continuing in an east direction along the Willow Branch-Goose Creek drainage divide two more shallow through valleys can be seen in section 15 linking a north-oriented Willow Branch tributary valley with a south and southeast oriented Goose Creek tributary valley and with a southeast-oriented Goose Creek tributary valley. Still further east in the section 11 southeast quadrant a shallow through valley links a north-oriented Shoal Creek tributary valley with a southeast-oriented Goose Creek tributary valley. These through valleys are shallow because prior to headward erosion of the deep Shoal Creek valley and its deep tributary valleys into the region all flood flow movements were in a south direction and the deep Goose Creek valley did not exist, nor did the deep Shoal Creek valley exist. Headward erosion of the deep northeast and east oriented Goose Creek valley in the figure 6 map area captured south oriented flood flow slightly in advance of headward erosion of the deep east-southeast oriented Shoal Creek valley, which beheaded and reversed flood flow routes to the newly eroded Goose Creek valley. Remember, flood flow routes were beheaded in sequence from east to west and were beheaded one at a time. Flood waters on newly reversed flood flow routes could capture south-oriented flood flow routes located west of the actively eroding Shoal Creek valley head. For example, the deep Willow Branch valley eroded headward in a southwest direction to capture south-oriented flood flow routes west of the actively eroding Shoal Creek valley and other north-northeast and northeast tributary valleys also eroded headward for the same reason.

• Figure 7 illustrates the Crabapple Creek-South Mud Creek drainage divide area located east and south of the figure 5 map area and includes overlap areas with figure 5. Polo is the town located near the figure 7 west center edge. Cowgill is the town near the figure 7 center and Braymer is the town straddling the figure 7 east edge (north half). Crabapple Creek is the north-oriented stream originating near Cowgill and flowing to the figure 7 north center edge. North of figure 7 Crabapple Creek flows to east-oriented Shoal Creek. West of Crabapple Creek is north-oriented Brush Creek and west of Polo is north-oriented Long Creek, both flowing to east-oriented Shoal Creek. The south-oriented stream originating between Polo and Cowgill and flowing the figure 7 south center edge is the East Fork Crooked River. South-oriented streams in the figure 7 southwest quadrant are East Fork Crooked River tributaries. South of the figure 7 map area the East Fork Crooked River joins the southeast-oriented Crooked River, which flows to the east-oriented Missouri River. Note how multiple shallow through valleys link the north-oriented Brush Creek and Crabapple Creek valleys with the south-oriented East Fork Crooked River valley. A somewhat different drainage pattern is found in the figure 7 east half. The northeast and north-northeast oriented stream in the figure 7 southeast quadrant and flowing to the figure 7 east edge south of Braymer is Mud Creek, which originates near the figure 7 south edge. The southeast-oriented Mud Creek tributary originating near Cowgill is South Mud Creek and joins northeast-oriented Mud Creek as a barbed tributary. The southeast-oriented tributary flowing across the figure 7 northeast quadrant and joining Mud Creek as a barbed tributary at the figure 7 east edge is North Mud Creek. Just north of the figure 7 map area the southeast-oriented North Mud Creek valley is linked by a well-defined through valley with the north-oriented Crabapple Creek near where Crabapple Creek enters the east-oriented Shoal Creek valley. And in the figure 7 northeast corner the southeast-oriented stream north of Braymer is Oak Branch, which also joins Mud Creek as a barbed tributary and which also north of the figure 7 map is linked by through valleys with the east-oriented Shoal Creek valley. What has happened in the east half of figure 7 map area is major flood flow reversals along what is now the north-oriented Mud Creek valley enabled headward erosion of the deep Mud Creek valley to capture southeast-oriented flood flow routes west of the actively eroding Shoal Creek valley. The southeast-oriented Oak Branch, North Mud Creek, and South Mud Creek valleys were eroded headward along southeast-oriented flood flow routes captured as the deep north-oriented Mud Creek valley eroded headward into the figure 7 map area.

• Figure 8 illustrates the Mud Creek-Turkey Creek drainage divide area south and east of the figure 7 map area and includes overlap areas with figure 7. Braymer is the town located near the figure 8 north center edge.  Cowgill is located in the figure 8 northwest quadrant. Crabapple Creek can be seen flowing in a north direction in the northwest corner. Mud Creek originates in the figure 8 southwest quadrant and flows in a northeast and north-northeast direction to the figure 8 north edge (just east of Braymer). Southeast-oriented South Mud Creek originates near Cowgill and joins northeast-oriented Mud Creek at the east edge of the figure 8 southwest quadrant. Note how south and east of where South Mud Creek joins Mud Creek there is a through valley and then a southeast oriented stream labeled as Cottonwood Creek. South of the figure 8 map area Cottonwood Creek joins southeast and east-oriented Wakenda Creek, which flows to and then along the Missouri River valley north edge to eventually reach the east-oriented Missouri River. The through valley provides evidence headward erosion of the deep northeast and north-northeast oriented Mud Creek valley captured a major southeast-oriented flood flow route to what was once the actively eroding Wakenda Creek valley. Other south-oriented streams east of Cottonwood Creek flowing to the figure 8 south edge are also Wakenda Creek tributaries, with other streams joining south-southeast and south oriented Turkey Creek before reaching Wakenda Creek. The north-oriented stream near the figure 8 northeast corner is a different Cottonwood Creek, which north of the figure 8 map area joins Shoal Creek. Note the through valley labeled as Low Gap, which links the north-oriented Cottonwood Creek valley with the south-oriented Turkey Creek valley. The map contour interval is ten meters and the Low Gap through valley is defined by at least four contour lines on each side and is easily recognizable without the aid of a more detailed map. The Low Gap through valley provides evidence of a major south-oriented flood flow route prior to headward erosion of the deep Shoal Creek valley, which beheaded the flood flow route and reversed flood waters on the north end of the beheaded flood flow route to erode the north-oriented Cottonwood Creek valley. Southeast-oriented flood flow routes captured by headward erosion of the deep northeast and north-northeast oriented Mud Creek valley were moving flood waters to the south-oriented Turkey Creek valley, which in turn was moving flood waters to the actively eroding Missouri River valley. Note northwest-oriented Mud Creek tributaries from the south and east and how they are aligned with southeast-oriented Turkey Creek headwaters and tributary valleys.

• Figure 9 provides a detailed topographic map of the Mud Creek-Cottonwood Creek drainage divide area seen in less detail in figures 7 and 8 above. Mud Creek flows in a north-northeast direction from the section 25 northwest corner across section 24 and into section 13 where it turns to flow in a northeast direction across section 18 and the section 17 northwest quadrant to the figure 9 north edge. South Mud Creek flows in a southeast direction from the figure 9 north center edge (just east of words “Little Union Ch”) to join Mud Creek near the section 18 eastern edge. North and east of the figure 9 map area Mud Creek eventually reaches Shoal Creek, which in turn flows to the Grand River. Cottonwood Creek originates in the section 25 northeast quadrant and flows in an east direction along the section 30 north margin to the section 20 south center margin and then turns to flow in a southeast direction across the section 29 northeast quadrant and into section 28 and then to the figure 9 south edge. South of figure 9 Cottonwood Creek joins southeast-oriented Wakenda Creek, which then flows to the east-oriented Missouri River valley. A southeast-oriented stream originating in the section 25 center and flowing to the figure 9 south center edge is a Wakenda Creek tributary. Note how that southeast-oriented Wakenda Creek tributary valley is linked by a shallow through valley in section 25 with the north-northeast oriented Mud Creek headwaters valley. Headward erosion of the north-northeast oriented Mud Creek valley beheaded southeast-oriented flood flow moving to the actively eroding Wakenda Creek valley and diverted flood water north and northeast to the Shoal Creek and Grand River valleys. A much deeper through valley is located in the section 17 southeast quadrant and links a south-southeast oriented Cottonwood Creek tributary valley with a north-northwest oriented Mud Creek tributary valley, which joins the northeast-oriented Mud Creek valley directly opposite the southeast-oriented South Mud Creek valley. The map contour interval is ten feet and the through valley floor elevation is between 820 and 830 feet. Elevations on both sides of the through valley rise to more than 940 feet. The through valley and the valley orientations provide evidence of a major southeast-oriented flood flow route to what was once the actively eroding Wakenda Creek valley, which was captured by headward erosion of the slightly deeper northeast-oriented Mud Creek valley. At first glance this evidence might be considered a simple stream capture event. However the previously mentioned section 25 through valley provides evidence that at the time of the South Mud Creek capture southeast-oriented flood flow was still moving to the Wakenda Creek valley along a much higher level flood flow channel, which is now the section 25 through valley. Enough southeast-oriented flood flow had been moving across the figure 9 map area after the Mud Creek capture of the southeast-oriented South Mud Creek flood flow channel to permit the Mud Creek valley to continue to erode headward to behead the southeast-oriented flood flow moving to the Wakenda Creek valley in section 25.

• Figure 10 provides a detailed map of the Cottonwood Creek-Turkey Creek drainage divide area seen in less detail in figure 8 above. The northeast oriented stream flowing through section 21 and 15 to the figure 10 north center edge is Cottonwood Creek, which north of the figure 10 map area flows to Shoal Creek, which in turn flows to the Grand River. Note the north-oriented Cottonwood Creek tributary located in section 22. The stream flowing in an east direction from section 28 into section 27 and then turning to flow in a south direction to the figure 10 south center edge is a tributary to south-oriented Turkey Creek, which south of the figure 10 map area flows to southeast-oriented Wakenda Creek, which in turns flows to the east-oriented Missouri River valley. Low Gap in the section 27 northwest quadrant is a well-defined north-south oriented through valley linking the north-oriented Cottonwood Creek valley with the south-oriented Turkey Creek valley. The map contour interval is ten feet and the Low Gap valley floor elevation is between 790 and 800 feet. Elevations on both sides of Low Gap rise to more than 930 feet. The Low Gap through valley provides evidence of a major south-oriented flood flow route to what was once the actively eroding Missouri River valley head, which was subsequently beheaded by headward erosion of the deep Grand River-Shoal Creek valley. Flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north oriented Cottonwood Creek valley. The north-northwest stream in the figure 10 northeast corner is a Cottonwood Creek tributary. Study of section 23 and 25 drainage divides reveals several much higher elevation through valleys crossing the drainage divide and providing evidence flood waters once flowed on a topographic surface at least as high as the highest figure 10 elevations today. Unlike through valleys seen further west along the Shoal Creek-Missouri River drainage this Low Gap through valley (and the section 17 through valley seen in figure 9) provides evidence of well-defined and easy to identify south-oriented flood flow channels which were subsequently beheaded and reversed by Shoal Creek valley headward erosion.

Additional information and sources of maps studied