• The purpose of this essay is to use topographic map interpretation methods to explore the Nodaway River-One Hundred and Two River drainage divide area landform origins in Andrew and Nodaway 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 Nodaway River-One Hundred and Two River drainage divide area landform evidence in Andrew and Nodaway 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 provides a location map for the Nodaway River-One Hundred and Two River drainage divide area in Andrew and Nodaway Counties, Missouri. The Missouri River flows in a south-southeast direction from Omaha, Nebraska in the figure 1 northwest corner to Kansas City and then in an east-northeast direction to Brunswick, Missouri before turning to flow in a southeast direction to the figure 1 south edge. South of the figure 1 map area the Missouri River turns to flow more in an east direction to join the south-oriented Mississippi River, which can be seen along the figure 1 east center edge. Nebraska is the state west of the Missouri River in the figure 1 northwest quadrant and Kansas is the state south of Nebraska. The state east of the Missouri River in the figure 1 north half is Iowa and Missouri is the state south of Iowa. A small area in Illinois can be seen east of the Mississippi River along the figure 1 east center edge. The south-southwest oriented East Nodaway River is labeled in the Iowa southwest corner region with the unlabeled West Nodaway River flowing parallel to it until the two branches join near the Iowa-Missouri border to form the south-oriented Nodaway River, which flows near Burlington Junction and Skidmore in northwest Missouri before joining the Missouri River. The One Hundred and Two River originates north of Bedford, Iowa (near Iowa-Missouri border) and flows in a south direction near Hopkins, Maryville, and Bolckow, Missouri before joining the parallel south-oriented Platte River near St. Joseph, Missouri, which then continues to flow in a south direction to join the Missouri River south of Platte City, Missouri (and slightly upstream from Kansas City). The Nodaway River-One Hundred and Two River drainage divide area in Andrew and Nodaway Counties, Missouri is located north of St. Joseph and south of the Iowa-Missouri state line.

• Note in figure 1 how Missouri River tributaries in southwest Iowa and northwest and north central Missouri are generally oriented in south directions while Mississippi River tributaries in northeast Missouri and southeast Iowa are generally oriented in southeast directions (with some northeast-oriented tributaries to southeast-oriented Mississippi River tributaries near the figure 1 north center edge). The Grand River, which joins the Missouri River near Brunswick, Missouri, flows for a considerable distance in Missouri in a southeast direction, but most Grand River tributaries from the north are oriented in south directions. The difference in tributary orientations makes it fairly easy to identify the Missouri River-Mississippi River drainage divide location on the figure 1 map. The Missouri River-Mississippi River drainage divide is a significant landform and was formed as the deep Mississippi and Missouri River valleys and their tributary valleys eroded headward into the figure 1 map region. The valleys eroded headward into the region during immense south-oriented floods as a thick North American ice sheet, located north of the figure 1 map area, rapidly melted. The ice sheet had been located in a deep “hole” created by deep glacial erosion and crustal warping caused by the ice sheet’s tremendous weight. The figure 1 map region was probably located along the south rim of that deep “hole” and was deeply eroded as repeated immense melt water floods flowed across the region. How deep the figure 1 regional erosion was probably cannot be determined, although it is possible hundreds of meters of bedrock material was stripped from the entire region.

• The immense south oriented melt water floods flowed to the Gulf Mexico and were gradually captured by headward erosion of Mississippi River tributary valleys probably as the large Mississippi River valley itself eroded headward from the Gulf of Mexico. South of the figure 1 map area the southeast-oriented Arkansas River valley eroded headward to capture the south oriented flood flow and to divert that captured flood flow to the Mississippi River valley prior to headward erosion of the White River valley (in Arkansas). Following White River valley headward erosion the deep Missouri River valley and its tributary valleys eroded headward across what is now the state of Missouri and beheaded flood flow routes to the newly eroded White River valley and Arkansas River valley. In western Missouri headward erosion of the deep Missouri River valley captured an especially large south-southeast oriented flood flow river which was emerging from the mouth of a giant ice-walled canyon (and eventually bedrock-floored), which had been carved into the decaying ice sheet’s surface. The huge melt water river emerging from that ice-walled canyon (in southeast South Dakota) drained a large region of the decaying ice sheet’s surface, which included much of present day eastern South Dakota, central and northern North Dakota, southern and central Saskatchewan, and east central Alberta, if not more. The northeast and east facing Missouri Escarpment is what remains of the ice-walled and bedrock-floored canyon’s southwest and west wall and the west-facing Prairie Coteau Escarpment in eastern South Dakota is a remnant of the canyon’s east wall. Capture of the immense south-southeast oriented river emerging from that ice-walled canyon’s mouth enabled the deep south-southeast oriented Missouri River valley to erode headward into southeast South Dakota. At the same time the east-oriented Kansas River valley and east-oriented Kansas River tributary valleys eroded headward from the Kansas City area to capture south- and southeast-oriented flood flow further to the west. Evidence for the southern end of the giant ice-walled and bedrock-floored canyon is described in essays listed under North Dakota and South Dakota on the sidebar category list (see especially essays related to the James River).

• Figure 2 provides a more detailed location map for the Nodaway River-One Hundred and Two River drainage divide area in Andrew and Nodaway Counties, Missouri. County names and boundaries are shown. The west to east oriented Iowa-Missouri state line is located near the figure 2 north edge. The Missouri River flows in a southeast direction from the figure 2 northwest corner to St. Joseph (near figure 2 south enter edge) and then turns to flow in a south-southwest direction to the figure 2 south edge. The figure 2 region east of the Missouri River is the state of Missouri. Brown and Doniphan Counties in the figure 2 southwest quadrant area are located in Kansas and Richardson and Nemaha Counties to the north (and west of the Missouri River) are located in Nebraska. The Nodaway River flows in a south direction from the figure 2 north edge (just west of center) across western Nodaway County and then along the Holt County eastern border to join the Missouri River. The One Hundred and Two River flows in a south direction from the figure 2 north center edge to Hopkins (located in northern Nodaway County) and just east of Maryville before continuing in a south direction across central Andrew County to join the south-oriented Platte River just east of St. Joseph. The Platte River flows in a south-southwest direction from the figure 2 north edge across the Worth County northwest corner  and into northeast Nodaway County where it turns to flow in a south direction across eastern Nodaway and Andrew Counties to join the parallel One Hundred and Two River just east of St. Joseph. South of the St. Joseph area and the figure 2 map area the Platte River flows in a south direction to eventually join the Missouri River (see figure 1). Note how in the Nodaway River-One Hundred and Two River drainage divide area in Nodaway and Andrew Counties most Nodaway River tributaries are oriented in south-southwest and southwest directions and White Cloud Creek, which is the major One Hundred and Two River tributary shown, is oriented in a south-southeast direction. However, there are some interesting exceptions. In northern Nodaway County an unnamed Nodaway River tributary near Clearmont flows in a south-southwest, north-northwest, and west direction. Further south in western Andrew County two different unnamed west-oriented Nodaway River tributaries have north-oriented tributaries. These north-oriented streams in a region dominated by south-oriented drainage systems are barbed tributaries and provide evidence of reversals of flood flow on north ends of beheaded south-oriented flood flow routes. The parallel and converging south-oriented figure 2 drainage systems provides evidence of what at one time was a south-oriented anastomosing channel complex. Note how both east and west of the Nodaway River the figure 2 drainage routes are also oriented in south directions and how in Brown and Doniphan Counties there are additional north-oriented streams.

• Figure 3 provides a reduced size topographic map of the Missouri River-One Hundred and Two River drainage divide area north of St. Joseph, Missouri. The Missouri River is meandering in the large south-southeast oriented valley along the figure 3 west edge. St. Joseph is the large city located on the Missouri River east bank and straddling the figure 3 south edge. Note how most tributaries flowing to the Missouri River valley are oriented in south and/or southwest directions, but how several of these tributaries have north-oriented (barbed) tributaries. The first south-oriented river east of the Missouri River valley flowing from the figure 3 north edge to the figure 3 south center edge is the One Hundred and Two River. The south-oriented river located east of the One Hundred and Two River and flowing from the figure 3 north edge to the figure 3 south center edge and joining the One Hundred and Two River just south of the figure 3 map area is the Platte River. As seen in figures 1 and 2 the Platte River then continues to flow in a south direction while the Missouri River makes a jog to the southwest before turning to flow in a southeast direction and to meet the south-oriented Platte River. Between the One Hundred and Two River and the Platte River in the figure 3 north half is south-oriented Long Branch, which is a One Hundred and Two River tributary. The south-oriented stream near the figure 3 east edge is the East Third Fork Platte River, which joins the southwest-oriented Little Third Fork in the figure 3 southeast quadrant and then joins the Platte River south of the figure 3 map area. Between the south-oriented Platte River and East Third Fork in figure 3 is south-oriented Muddy Creek, which originates near the figure 3 north edge. Note how many tributaries to the south-oriented trunk streams in figure 3 from the west are oriented in southeast directions and how at least some of the tributaries from the east are oriented in northwest directions. The closely spaced and roughly parallel elongated converging river and stream valleys suggests the valleys originated as channels in what was once a south-oriented anastomosing channel complex. A close look at drainage divides reveals shallow through valleys linking headwaters of southeast-oriented tributary valleys to the east with west-oriented tributary valleys to the west. The through valleys are relics of abandoned southeast-oriented diverging and converging channels beheaded as the deep south-oriented valleys eroded headward from what was then the newly eroded and deep Missouri River valley.

• Figure 4 provides a topographic map of the Lincoln Creek-Missouri River drainage divide area north and west of the figure 3 map area. An east-oriented Missouri River valley segment can be seen along the figure 4 southwest quadrant south edge. The south-oriented One Hundred and Two River flows from the figure 4 north edge to the south edge in the figure 4 east half. Note how in the figure 4 northeast quadrant there are several north, north-northeast, and northeast oriented One Hundred and Two River tributaries. These north-oriented barbed tributaries flow to a south-oriented river. Note how north and north-northeast oriented headwaters of these One Hundred and Two tributaries are linked by shallow through valleys with headwaters of south and south-southwest oriented Missouri River tributaries. The valley orientations and the shallow through valleys provide evidence of what were once diverging and converging channels in a south-oriented anastomosing channel complex. Headward erosion of the deep south-oriented One Hundred and Two River valley beheaded south-southwest oriented flood flow channels to what were then actively eroding deep south-southwest oriented Missouri River tributary valleys. Flood waters on north-northeast ends of the beheaded flood flow channels reversed flow direction to erode the north, north-northeast, and northeast oriented One Hundred and Two River tributary valleys. The south-oriented Nodaway River forms the Holt-Nodaway County line near the figure 4 west edge. Lincoln Creek originates near the figure 4 center and flows in a north and north-northwest direction to the north center area and then turns to flow in a south-southwest and west-northwest direction to join the south-oriented Nodaway River. Note how the north and north-northwest oriented Lincoln Creek headwaters valley and a north-oriented Lincoln Creek tributary valley are linked by shallow through valleys to the south-oriented Caples Creek and Mill Creek valleys. Again the north-oriented Lincoln Creek headwaters and the unnamed north-oriented Lincoln Creek tributary are barbed tributaries. The north-oriented valleys were eroded by reversals of flood flow on beheaded south-oriented flood flow channels. The deep Caples Creek and Mill Creek valleys had been eroding headward from the newly eroded Missouri River valley until headward erosion of the deep south-oriented Nodaway River valley enabled the deep west and south-southwest oriented Lincoln Creek valley to erode headward across the south-oriented flood flow channels and to divert the flood flow to the newly eroded and deeper Nodaway River valley.

• Figure 5 provides a detailed map of the Lincoln Creek-Caples Creek drainage divide area seen in less detail in the figure 4 map above. Lincoln Creek originates in section 1 near the figure 5 center and flows in a north and north-northwest direction to the figure 5 north center edge. Caples Creek also originates in section 1 and flows in a south direction to the figure 5 south edge (just east of center). Mill Creek is the south-southwest, west, southwest, and south oriented stream in the figure 5 southwest quadrant flowing to the figure 5 south edge (near the section 16-15 boundary). North-oriented streams in section 34 (figure 5 northeast quadrant) are Lincoln Creek tributaries. Mill Creek and Caples Creek as seen in figure 4 are south-oriented Missouri River tributaries. West-oriented streams flowing from the figure 5 west center area are headwaters of west-oriented Honey Creek, which flows to the south-oriented Nodaway River west of the figure 5 map area (see figure 4). Note the multiple shallow through valleys in section 1 linking the north-oriented Lincoln Creek headwaters valley with the south-oriented Caples Creek headwaters valley. The map contour interval is ten feet and floors of the deepest through valleys have an elevation of between 1110 and 1120 feet. The hill-top in the section 2 east center area is labeled s having an elevation of 1172 feet and a hilltop at the north end of the landing strip in section 6 has a spot elevation of 1166 feet. Additional through valleys can be seen in section 6 (near west edge) and in the section 2 southeast corner. Also note in sections 2 and 3 many more through valleys linking north-oriented Lincoln Creek tributary valleys with south-oriented Mill Creek tributary valleys. These multiple through valleys provide evidence of multiple south-oriented flood flow channels which once moved flood water to the actively eroding Mill Creek and Caples Creek valleys. At that time the deep west-oriented Lincoln Creek valley north of the figure 5 map area did not exist, nor did other deep Nodaway River and One Hundred and Two River (and other river) valleys exist. South-oriented flood flow moving from the ice sheet margin (north of the study region) was able to move freely into the figure 5 map area to the actively eroding south-oriented tributary valleys eroding headward from the newly eroded southeast-oriented Missouri River valley.

• Figure 6 uses a reduced size topographic map to illustrate the Pedlar Creek-Lincoln Creek drainage divide area north of the figure 4 map area and includes overlap areas with figure 4. The One Hundred and Two River flows from the figure 6 north edge (east half) in a south-southeast direction to the figure 6 southeast corner. Note north-northeast oriented One Hundred and Two River tributaries. The Nodaway River flows in a south, southeast, and south direction from the figure 6 northwest corner to the figure 6 south edge (west half). Note northeast and east-southeast oriented Carroll Branch in the figure 6 southwest corner. Lincoln Creek flows in a north-northwest, south-southwest, and west direction in the figure 6 south center area to reach the south-oriented Nodaway River. Arapahoe Creek is the west-southwest and south oriented stream flowing across the figure 6 north center area to join the Nodaway River in the figure 6 west center area. Pedlar Creek is the west and west-southwest tributary joining Arapahoe Creek just north of where Arapahoe Creek joins the Nodaway River. Owl Creek is the southwest and south oriented Arapahoe Creek tributary in the figure 6 northwest quadrant. Note how Pedlar Creek and Arapahoe Creek have northwest and north oriented tributaries. Close study of the figure 6 map area reveals shallow through valleys eroded across the Pedlar Creek-Lincoln Creek drainage divide and also across the Arapahoe Creek-Pedlar Creek drainage divide. The through valleys link north-oriented tributary valleys with south-oriented tributary valleys and are best seen on more detailed topographic maps. Figure 7 provides a detailed topographic map of the Arapahoe Creek-Pedlar Creek drainage divide area to illustrate through valleys there. What has happened in the figure 6 map area is the One Hundred and Two River valley eroded headward into the figure 6 map area slightly in advance of the Nodaway River valley and beheaded and reversed southwest and south-southwest oriented flood flow channels to reverse flood waters on northeast and north-northeast ends of the beheaded channels so as to erode the northeast and north-northeast oriented One Hundred and Two River tributary valleys. Next headward erosion of the deep Nodaway River valley enabled the Lincoln Creek valley to erode headward and to behead and reverse flood flow channels so as to erode the north-oriented Lincoln Creek headwaters valley and tributary valleys. Pedlar Creek valley headward erosion followed and beheaded and reversed flood flow routes to the newly eroded Lincoln Creek valley and Arapahoe Creek valley headward erosion repeated the process.

• Figure 7 provides a detailed topographic map of the Arapahoe Creek-Pedlar Creek drainage divide area seen in less detail in figure 6 above. Arapahoe Creek flows in a west-southwest, southwest, and south direction from the figure 7 northeast corner area to the figure 7 southwest corner. Owl Creek is the south-oriented tributary joining the Arapahoe River in section 19. Pedlar Creek flows in a west and west-southwest direction near the figure 7 south edge and joins Arapahoe Creek near the figure 7 southwest corner. This map is difficult one to read because different contour intervals are used in different places. West of Owl Creek the contour interval is ten feet. East of Owl Creek and the south-oriented Arapahoe Creek segment there is region where the contour interval is 4 meters and further east the map contour interval is 5 meters. With that said follow the Arapahoe Creek-Pedlar Creek drainage divide across the figure 7 map area and note the multiple shallow north-south oriented through valleys crossing that drainage divide. Some of the through valleys are defined by only a single contour line on each side, other through valleys are defined by two or three contour lines on each side. None of the through valleys is deep, yet the through valleys provide evidence of multiple south-oriented flood flow channels that existed prior to erosion of the deep Arapahoe Creek valley. Flood waters were moving to what were then actively eroding south-oriented tributary valleys which had eroded headward from what was then the newly eroded Pedlar Creek valley. Headward erosion of the Arapahoe Creek valley then captured the south oriented flood flow and beheaded flood flow routes to the newly eroded Pedlar Creek valley. North and northwest oriented Arapahoe Creek tributary valleys were eroded by reversals of flood flow on north and northwest ends of beheaded flood flow routes. Probably the Pedlar Creek and Arapahoe Creek valleys eroded across the figure 7 map area at approximately the same time with Pedlar Creek valley headward erosion being slightly in advance of Arapahoe Creek valley headward erosion.

• Figure 8 provides a topographic map of the Nodaway River-White Cloud Creek drainage divide area north of the figure 6 map area (there is no overlap with figure 6). Skidmore is the town located in the figure 8 northwest corner, Maitland and Graham are the two towns in the southwest quadrant, and Barnard is the town near the southeast corner. The One Hundred and Two River flows in a south direction near the figure 8 east edge. White Cloud Creek is the south-southeast oriented stream in the figure 8 east half and south of figure 8 joins the One Hundred and Two River. The Nodaway River flows in a south direction near the figure 8 west edge. Elkhorn Creek is the southwest and south-southwest oriented stream joining the Nodaway River near the figure 8 southwest corner. Jenkins Creek is the south-southwest and west-southwest oriented Nodaway River tributary located east and south of Elkhorn Creek. The westernmost of two south-oriented streams flowing to the figure 8 south center edge is Owl Creek and the stream east of Owl Creek is Newland Creek, which is another Arapahoe Creek tributary. Note how the south-southwest oriented Newland Creek valley is linked by shallow through valleys with both the west-northwest oriented East Fork Jenkins Creek valley and an unnamed east-oriented White Cloud Creek valley. These through valleys provide evidence of diverging and converging channels that existed prior to headward erosion of present day valleys. Further north note a west-northwest oriented Jenkins Creek headwaters valley is linked by shallow through valleys with the south-southeast oriented White Cloud Creek valley. These through valleys provide further evidence of anastomosing channels crossing the figure 8 map area at a time when flood waters were freely moving across what are today drainage divides. Again the through valleys are better seen on more detailed topographic maps and even then are shallow and nor spectacular features. Yet the through valleys and the elongate and parallel drainage basins provide evidence of flood flow channels that eroded the figure 8 map region just prior to headward erosion of present day deep valleys. Figure 9 below provides a detailed topographic map of the White Cloud Creek-Arapahoe Creek drainage divide area located south of the figure 8 southeast quadrant.

• Figure 9 provides a detailed map of the White Cloud Creek-Arapahoe Creek drainage divide area and is located south of the figure 8 southeast quadrant and north of the figure 6 northeast quadrant. Note the west to east oriented Nodaway-Andrew County line near the figure 9 south edge. The One Hundred and Two River flows in a south direction from the figure 9 northeast corner to the southeast corner with a jog across the figure 9 east edge (north half). White Cloud Creek is south-southeast and southeast oriented tributary joining the One Hundred and Two River near the figure 9 southeast corner. The town of Barnard is located just east of the figure 9 northeast corner. The south-southwest oriented streams flowing to the figure 9 south edge (center and west half) and west edge (south half) are Arapahoe Creek headwaters and tributaries, with Newland Creek being the labeled stream flowing to the figure 9 west edge (south half). Arapahoe Creek as seen in figure 6 flows to the Nodaway River. Study the drainage divide between the heads of the south-southwest oriented Arapahoe Creek headwaters and tributary valleys and the White Cloud Creek valley and note multiple shallow through valleys. For example in the section 31 northeast quadrant a north-oriented through valley links a northeast-oriented White Cloud Creek tributary valley with a south-oriented Arapahoe Creek tributary valley. The valley orientations and the through valleys provide evidence headward erosion of the deep south-southeast oriented White Cloud Creek valley beheaded multiple south-southwest oriented flood flow routes to what were then actively eroding Arapahoe Creek headwaters and tributary valleys. The south-southwest oriented flood flow routes provide further evidence of the existence of anastomosing south-oriented flood flow channels crossing what is now the Nodaway River-One Hundred and Two River drainage divide. Study of the figure 9 map area also reveals through valleys crossing drainage divides between the various Arapahoe Creek tributary and headwaters valleys. For example on the boundary between section 35 and section 26 a through valley links a northwest-oriented Newland Creek tributary valley with a southeast-oriented tributary valley to the south-southwest oriented Arapahoe Creek headwaters valley.

• Figure 10 provides a reduced size topographic map of the Nodaway River-One Hundred and Two River drainage divide area north of Maryville, Missouri and is north of the figure 8 map area (with no overlap). Maryville is the large town located near the south edge of the figure 10 southeast quadrant. The One Hundred and Two River is located in the large south-oriented valley east of Maryville. The Nodaway River flows in the large south-oriented valley in the figure 10 west half. Clear Creek is the southwest and west oriented stream joining the Nodaway River near Clearmont (near figure 10 north edge). Note how Clear Creek has a south-southwest and north-northwest tributary in the figure 10 center region, which is the South Fork Clear Creek. Mill Creek is the south-southeast oriented stream joining the Nodaway River near Burlington Junction. Note the south-southwest oriented White Cloud Creek headwaters west and north of Maryville. Big Slough is the southwest and south-southeast oriented stream joining White Cloud Creek near the figure 10 south center edge. South of the figure 10 map area White Cloud Creek flows in a south-southeast direction as seen in figures 8 and 9. Note how the south-southwest and north-northwest oriented South Fork Clear Creek valley at its elbow of capture is linked by a well-defined north-northwest to south-southeast oriented through valley with the south-southeast oriented Big Slough-White Cloud Creek valley. The map contour interval is ten meters and the through valley is defined by two contour lines on each side. The map grid is based on sections which are one mile on a side and the through valley is more than one mile across (more if measurements are made from the valley rims). The through valley provides evidence the south-southwest and north-northwest oriented South Fork Clear Creek valley segments originated as converging south-oriented flood flow channels moving flood waters to the White Cloud Creek channel. The south-oriented flood flow was captured by Nodaway River valley headward erosion combined with headward erosion of the west-oriented Clear Creek valley. Flood waters on the north-northwest end of the beheaded south-southeast oriented flood flow channel reversed flow direction to erode the north-northwest oriented South Fork Clear Creek valley and also to capture the south-southwest oriented flood flow channel on what is today the south-southwest oriented South Fork Clear headwaters valley alignment, which created the South Fork Clear Creek elbows of capture.

Additional information and sources of maps studied