Abstract:
Topographic map interpretation methods are used to determine landform origins in the Missouri River-Meramec River drainage divide area located in St Louis and Franklin Counties, Missouri. The study region is bounded on the north by southeast and northeast oriented Missouri River valley segments, on the south by northeast, east, and southeast oriented segments of the meandering Meramec River valley and its meandering northeast and southeast oriented Bourbeuse River tributary valley and on the east by the south-oriented Mississippi River. Study region landforms evolved during immense south oriented glacial melt water floods, which flowed across the entire region. Evidence for the immense flood flow include valley orientations, elbows of capture, barbed tributaries, and through valleys eroded across drainage divides. North-oriented valleys were eroded by reversals of flood flow along north ends of beheaded flood flow routes. Because flood flow routes were beheaded and reversed in sequence, from east to west, newly reversed flood flow routes could capture yet to be beheaded flood flow routes located further to the west. These captures established northeast-oriented flood flow routes responsible for northeast-oriented tributary valley erosion and also complex flood flow movements responsible for eroding Meramec and Bourbeuse River incised meanders. Headward erosion of the Meramec and Bourbeuse River valleys occurred prior to Missouri River valley headward erosion, which beheaded and reversed flood flow routes to the newly eroded Meramec River and Bourbeuse River valleys.
Preface:
The following interpretation of detailed topographic map evidence is one of a series of essays describing similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored deep glacial erosion paradigm, which is fundamentally different from most commonly accepted North American glacial history interpretations. Project essays available at this site may be found by selecting desired Missouri River tributaries and/or states from this essay’s sidebar category list.
Introduction:
- The purpose of this essay is to use topographic map interpretation methods to explore the Missouri River-Meramec River drainage divide area landform origins in St Louis and Franklin 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 Missouri River-Meramec River drainage divide area landform evidence in St Louis and Franklin 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.
Missouri River-Meramec River drainage divide area location map
Figure 1: Missouri River-Meramec River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.
- Figure 1 is a location map for the Missouri River-Meramec River drainage divide area in St Louis and Franklin Counties, Missouri. The Mississippi River flows in a south-southeast direction (with a northward jog) from the figure 1 north edge to the south edge and is the boundary between Missouri to the west and Illinois to the east. The Missouri River flows in a northeast direction from the figure 1 west edge (near northwest corner) to Brunswick (near west edge) and then turns to flow in a southeast, south, east, and southeast direction to Jefferson City. From Jefferson City the Missouri River flows in an east-northeast, southeast, and northeast direction to join the south-oriented Mississippi River near its northward jog. The Meramec River flows in a north-northwest direction from the figure 1 south center edge to near St James (just east of Rolla) and then turns to flow in an east-northeast and northeast direction to Kirkwood (just west of St Louis). At Kirkwood the Meramec River turns to flow in south-southeast direction to join the Mississippi River near Arnold. The Bourbeuse River is a northeast-oriented tributary which turns to flow in a south direction to join the northeast-oriented Meramec River south and east of Union (south of Washington). Note how other Meramec River tributaries from the south flow in flow north directions to join the northeast-oriented Meramec River. The Missouri River-Meramec River drainage divide area in St Louis and Franklin Counties, Missouri is south of the northeast-oriented Missouri River segment downstream from Washington. Essays describing drainage divide areas directly to the north include the Peruque Creek-Missouri River drainage divide area landform origins in Warren and St Charles Counties, Missouri essay and the Mississippi River-Missouri River drainage divide area landforms in St Charles County, Missouri essay. These and other essays describing other regional Missouri River drainage basin drainage divide areas can be found by selecting Missouri or MO Missouri River from the sidebar category list.
- Perhaps one of the most intriguing features about the Missouri River-Meramec River drainage divide area is how the both the Missouri River and Meramec River flow in northeast directions to join a south-oriented river, which also turns to flow in a north direction to meet the south-oriented Illinois River before flowing in a southeast and south direction again. Based on evidence presented in the topographic maps illustrated and described in this essay and also on topographic map evidence illustrated for other Missouri River drainage basin drainage divide areas, including for the entire Missouri River drainage basin region, figure 1 drainage routes evolved during massive south-oriented glacial melt water floods. Flood waters were derived from a rapidly melting thick North American ice sheet, which at the time figure 1 drainage routes were formed, was located north of the figure 1 map area. Melt water floods initially overwhelmed whatever drainage systems existed and flowed across the entire figure 1 map area directly to the Gulf of Mexico. Headward erosion of the large south-oriented Mississippi River valley and its tributary valleys systematically (from south to north) captured the south-oriented flood flow and diverted flood waters to the evolving Mississippi River and tributary valley system. For example, south of the figure 1 map area in the state of Arkansas headward erosion of the southeast-oriented Arkansas River valley and its tributary valleys captured the south-oriented flood flow prior to headward erosion of the southeast-oriented White River valley, which beheaded flood flow to the newly eroded Arkansas River valley and its tributary valleys. South-oriented White River tributary valleys then eroded headward into southern Missouri (just south of the figure 1 south edge).
- Headward erosion of the south-southeast and east oriented Meramec River valley segments in the St Louis area probably beheaded and reversed south-oriented flood flow, which had been moving to actively eroding south-oriented White River tributary valleys (and also to other shorter Mississippi River tributary valleys) while headward erosion of the deep Mississippi River valley beheaded and reversed southwest-oriented flood flow routes on what is now the northeast-oriented Missouri River valley segment. These flood flow reversals resulted in the erosion of the northeast-oriented Meramec River valley segment and its north-oriented tributary valleys and also in erosion of the northeast-oriented Missouri River valley. Headward erosion of the northeast-oriented Meramec River valley occurred first and the south-southeast oriented Bourbeuse River valley segment eroded headward along a major south-oriented flood flow route which was subsequently beheaded by headward erosion of the deep northeast-oriented Missouri River valley. Instead of continuing westward as a northeast-oriented valley along the reversed flood flow route the Missouri River then eroded headward along the capture flood flow route as a southeast-oriented valley, which eventually was able to erode headward across the entire state of Missouri and much further to the west as it and its tributary valleys captured the massive south-oriented flood flow. While massive reversals of south-oriented floods to erode what are today major north-oriented valleys seems intuitively impossible in the context of modern river systems, and the largest known historic floods, the immense south oriented floods were derived from a rapidly melting North American ice sheet, which contained sufficient water volumes to completely change the North American landscape. More specifically, the flood flow reversals occurred in sequence from east to west, meaning reversed flood flow routes could capture yet to be beheaded flood flow further to the west. These captures not only supplied water volumes required to erode significant north-oriented valleys, but also account for the Meramec River, Bourbeuse River, and other northeast-oriented drainage routes seen in figure 1.
Detailed location map for Missouri River-Meramec River drainage divide area
Figure 2: Detailed location map for Missouri River-Meramec River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 2 illustrates a more detailed location map for the Missouri River-Meramec River drainage divide area in St Louis and Franklin Counties, Missouri. County names and boundaries are shown. The Mississippi River flows in a south direction from the figure 2 north center edge to the St Charles County, Missouri north edge and then makes its jog to the north and then flows in a southeast direction along the St Charles County northern boundary to reach Alton in Madison County, Illinois. From Alton the Mississippi River turns to flow in a south-southwest direction past the St Louis urban area before turning to flow in a south-southeast direction near the figure 2 south edge. Remember, areas east of the Mississippi River are in Illinois and areas west of the river are in Missouri. The Missouri River flows in an east direction along the Montgomery County south edge before turning to flow in an east-southeast direction along the Warren County south border (and the Franklin County north border). Near the Warren County-St Charles County border the Missouri River turns to flow in a northeast direction almost to the southeast-oriented Mississippi River. But before joining the Mississippi River the Missouri River turns to flow in a southeast direction roughly parallel with the Mississippi River. The final southeast-oriented Missouri River segment is located in the Mississippi River valley with the Missouri River channel located on the valley’s southwest margin and the Mississippi River channel on the northeast margin. The Meramec River meanders in a northeast direction from the figure 2 south edge to Meramec State Park (located along the Franklin County south center border to Pacific (near the Franklin County, St Louis County, Jefferson County common corner). From near Pacific the Meramec River meanders in an east-northeast direction to Kirkwood in the St Louis urban area. Near Kirkwood the Meramec River turns to flow in a south-southeast direction along the Jefferson County-St Louis County border (northeast corner of Jefferson County) to join the Mississippi River near Arnold. Because figure 2 and the digital topographic maps being used for illustrations in this essay are difficult to read in the St Louis urban area this essay will emphasize Missouri River-Meramec River drainage divide areas west of the St Louis urban area. The major Meramec River tributary in the study region is the Bourbeuse River which meanders in a northeast direction from the figure 2 southwest corner area across the Gasconade County south margin to near Union in Franklin County. Near Union the Bourbeuse River turns so as to meander in a southeast direction to join the Meramec River near Moselle. North of the Bourbeuse River in Franklin County is northeast-oriented St Johns Creek, which joins the Missouri River a short distance upstream from Washington. Note how the northeast-oriented Meramec River has several northwest and north-oriented tributaries from the southeast and south, which are flowing in an opposite direction to that of the nearby Mississippi River. As previously mentioned the north-oriented valleys and the north-oriented regional slope were eroded by massive flood flow reversals as what was then the deep Missouri River valley eroded headward from the deep Mississippi River valley. Missouri River valley headward erosion proceeded from east to west and beheaded south-oriented flood flow routes in sequence from east to west. Reversed flood flow on newly beheaded flood flow routes could capture flood flow from yet to be beheaded flood flow routes further to the west. Such captures of flood flow provided the waters volumes required to erode the north-oriented slope and north-oriented river and tributary valleys.
Meramec River-Meramec River drainage divide area
Figure 3: Meramec River-Meramec River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 3 illustrates the Meramec River-Meramec River drainage divide area located on the southwest side of the St Louis urban area. The Meramec River meanders in a southeast direction from the figure 3 west center and turns to flow in a north-northeast direction to near the abandoned town of Times Beach. At Times Beach the Meramec River meanders in a northwest and north direction to near the figure 3 northwest corner. From the northwest corner the Meramec River flows in an east and east-northeast direction to near the figure 3 north edge and then turns to flow in a south-southeast direction into the figure 3 southeast quadrant. Once in the southeast quadrant the Meramec River turns to flow in an east direction to the figure 3 east edge. East of the figure 3 map area the Meramec River turns again to flow in a south direction to join the south-oriented Mississippi River. The north-oriented tributary with the S-shaped incised meander just before it joins the Meramec River near the figure 3 west edge is Big River. Note how Meramec River tributaries west of the figure 3 center area are predominantly oriented in north directions, while tributaries from the west to the south-oriented Meramec River segment in the figure 3 east half are oriented in southeast and east directions, although they usually have northeast-oriented headwaters and/or tributaries. For example, note Saline Creek, which begins near Parkdale and flows in a northeast direction to Murphy (in figure 3 center) and then turns to flow in a southeast direction to join the Meramec River near Pauline Hills in the figure 3 southeast quadrant. What has happened is the deep Meramec River valley first eroded headward from the actively eroding (and deep) Mississippi River valley along and across south- and southeast oriented flood flow routes already captured by headward erosion of the deep Mississippi River valley. West of the actively eroding deep Mississippi River valley however were yet to be captured (by the Mississippi River valley head) flood flow routes leading to actively eroding southeast-oriented Mississippi River tributary valleys located just south of the figure 3 map area (see Rock Creek in figure 2). Headward erosion of the deep south, east, and southeast oriented Meramec River and its east- and southeast-oriented tributary valley segments encountered these localized southwest-oriented flood flow routes and eroded headward across them. Flood flow reversals on northeast ends of beheaded flood flow routes then eroded the northeast-oriented tributary valley segments. When headward erosion of the deep Meramec River valley reached the figure 3 north edge it began to encounter and behead south-oriented flood routes and changed the direction in which it was eroding so as erode headward across the south-oriented flood flow routes. Flood waters on north ends of the beheaded flood flow routes then reversed flow direction to erode the north-oriented Meramec River tributary valleys and the north-oriented Meramec River valley segment near the figure 3 west edge. The north-oriented Big Creek valley was eroded by reversed flood flow, which south and west of the figure 3 map area successfully captured significant yet to be beheaded and reversed south-oriented flood flow (at that time the deep Meramec and Missouri River valleys had not yet eroded headward across the region). Remember, flood flow routes were beheaded and reversed one at a time from east to west, meaning reversed flood flow on newly beheaded flood flow routes could capture yet to be beheaded flood flow routes located further to the west.
Missouri River-Meramec River drainage divide area
Figure 4: Missouri River-Meramec River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 4 illustrates the Missouri River-Meramec River drainage divide area located north and west of the figure 3 map area and includes overlap areas with figure 3. The north-northeast oriented Missouri River flows across the figure 4 northwest corner. North of the figure 4 map area the Missouri River flows in more of an east-northeast direction and the south edge of the east-northeast oriented Missouri River valley can be seen along the figure 4 north margin. Note how north and northeast oriented Missouri River tributaries from the south often have northwest oriented headwaters and/or tributaries and how west-oriented tributaries from the east have northwest oriented tributaries and/or headwaters. The Meramec River flows in a north direction from the figure 4 south center edge and then turns to flow in an east direction to the figure 4 east edge. Note how Meramec River tributaries from the north and west are oriented in southeast and east directions. Visualizing how these northwest, north, and west oriented were eroded by reversals of flood flow routes as the deep Missouri River valley eroded headward across the region may be easier with the Missouri River valley than with the Meramec River valley in figure 3. Headward erosion of the deep Meramec River valley captured the south-oriented flood flow first and locally altered flood flow directions so significant flood water volumes were flowing in southeast and east directions to reach the actively eroding and deep Meramec River valley. This southeast and east oriented flood flow movement began to erode the southeast and east oriented Meramec River tributary valleys. Next headward erosion of the deep Missouri River (and its northeast-oriented tributary valleys) began to behead flood flow routes to the actively eroding Meramec River tributary valleys. Flood flow routes were beheaded in sequence (from east to west) as the deep Missouri River valley eroded headward. Flood waters on north, northwest, and west ends of beheaded flood flow routes reversed flow direction to erode the north-, northwest-, and west-oriented Missouri River tributary valleys. The north-northeast oriented Missouri River valley was eroded headward along what was a beheaded south-oriented flood flow route. Hamilton Creek is the southeast-oriented tributary flowing to the Meramec River elbow of capture (where it turns from flowing in a north direction to flowing in an east direction). Note how just west of Meramec Rockwoods Reservation is the small town of Fox Creek. At Fox Creek northwest-oriented headwaters of north and north-northeast oriented Wildhorse Creek are aligned with southeast-oriented Hamilton Creek. Also note how Wildhorse Creek has southeast-oriented tributaries from the west. Headward erosion of the deep north and north-northeast oriented Wildhorse Creek valley captured southeast-oriented flood flow moving to the actively eroding southeast-oriented Hamilton Creek valley. Flood waters on the northwest ends of the beheaded flood flow routes reversed to erode the northwest-oriented Wildhorse Creek headwaters and tributary valleys. Next headward erosion of the deep north-northeast oriented Missouri River valley segment (by reversed flood flow) beheaded flood flow routes to the newly eroded Wildhorse Creek valley.
Detailed map of Wildhorse Creek-Hamilton Creek drainage divide area
Figure 5: Detailed map of Wildhorse Creek-Hamilton Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 5 illustrates a detailed topographic map of the Wildhorse Creek-Hamilton Creek drainage divide area seen in less detail in figure 4 above. Fox Creek is faintly visible town in section 9 near the figure 5 center. East of Fox Creek are south-southeast oriented headwaters of southeast-oriented Hamilton Creek, which flows to the figure 5 east edge (south half). The east-northeast oriented stream near the south edge of the figure 5 southeast quadrant is Carr Creek, which east of the figure 5 map area joins Hamilton Creek, which in turn flows to the Meramec River. Wildhorse Creek flows in a northwest direction from the figure 5 center region (south of Fox Creek) to the north edge (near the northwest corner). Tavern Creek is the northwest-oriented stream flowing to the figure 5 west edge (just north of center). North-oriented streams flowing to the north edge of the figure 5 northeast quadrant are headwaters of northwest and northeast oriented Bonhomme Creek, which is a Missouri River tributary (see figure 4). Hollow is a small town located in the southwest-oriented valley near the south edge of the figure 5 southwest quadrant. The southwest-oriented stream at Hollow is a tributary to south-southeast and southeast oriented Fox Creek, which flows to the Meramec River south of the figure 5 map area. At first glance it may be difficult to see how the figure 5 drainage system evolved as deep valleys eroded headward into the region to capture massive south-oriented flood flow. But, begin to follow the drainage divides and observe how opposing valleys are often linked by very shallow through valleys crossing the drainage divide. The map contour interval is ten feet and the through valleys are usually defined by only one or two contour lines on each side. The shallow through valleys are perhaps easiest to see along the Bonhomme Creek-Hamilton Creek drainage divide in the figure 5 northeast quadrant, however follow the Wildhorse Creek-Hamilton Creek drainage divide south of the town of Fox Creek and note a through valley linking the northeast-oriented Wildhorse Creek valley with an east-oriented Hamilton Creek headwaters valley. This through valley is defined by two contour lines on each side and provides evidence of a southeast-oriented flood flow channel to what was once the actively eroding east- and southeast-oriented Hamilton Creek valley, which had eroded headward from what was then the actively eroding and deep Meramec River valley. At that time the deep Missouri River valley did not yet exist and flood waters were flowing on a topographic surface as high as the present day figure 5 drainage divides. Headward erosion of the deep Missouri River valley beheaded and reversed the southeast-oriented flood flow so as to erode the northwest-oriented Wildhorse Creek valley. The figure 5 drainage pattern is complicated and I will not try to unravel details (it might prove to be a good thesis project for a graduate student), But, the valley orientations and the shallow through valleys pointed out here do document the flood erosion origin.
Missouri River-Fox Creek drainage divide area
Figure 6: Missouri River-Fox Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 6 illustrates the Missouri River-Fox Creek drainage divide area located west and south of the figure 4 map area and includes overlap areas with figure 4. The east-northeast and northeast oriented Missouri River is located in the figure 6 northwest quadrant. Labadie Creek is the north-oriented tributary flowing from near Gray Summit in the figure 6 southwest quadrant to join the Missouri River near the Power Plant on the Labadie Bottoms area. Fiddle Creek is the north-oriented tributary east of Labadie Creek and entering the Missouri River valley at the town of Oettera. Tavern Creek is the northwest-oriented stream flowing to the Missouri River valley at St Albans (at Labadie Bottoms northeast end). Little Tavern Creek is the north-northwest oriented Missouri River tributary located directly south of St Albans. Pacific is the larger town located in the figure 6 south center area and is located on the north side of the meandering Meramec River valley. The northeast-oriented Meramec River enters the figure 6 map area just south of Shaw Arboretum (located south of Gray Summit) and then meanders in an east direction along the figure 6 south margin before meandering in more of a north direction along and across the figure 6 east edge. Southeast-oriented Hamilton Creek is located in the figure 6 northeast quadrant and joins a Meramec River meander near the figure 6 east edge. Fox Creek is the south-southeast and southeast oriented tributary flowing along the west side of the Rockwoods Range and joining the Meramec River at the north end of a meander just west of Allenton. Little Fox Creek is an east-oriented tributary flowing in a relatively straight valley across the figure 6 center area and is located just north the meandering Meramec River valley. Brush Creek is another relatively straight Meramec River tributary originating in the BOLES township area in the figure 6 southwest quadrant and joining the Meramec River near Pacific. The large meanders are incised meanders and were formed as the deep Meramec River valley eroded headward across the region. Incised meanders are relatively common along north-oriented rivers located south of the Missouri River in this region and are much rarer on south-oriented Missouri River tributaries. The north-oriented river valleys were eroded by flood flow reversals, which resulted in complex flood water movements with reversed flood flow eroding deep north-oriented valleys adjacent to yet to be beheaded south-oriented flood flow moving on a higher level topographic surface. The actively eroding north-oriented valley captured the yet to be beheaded south-oriented flood flow resulting in an eastward flood flow movement. The deep valley then eroded headward along that eastward oriented flow until it captured a south-oriented flood flow route. Then the deep valley eroded headward along the south-oriented flood flow route until it captured flood flow from yet to be beheaded flood flow routes still further to the west. Again the deep valley eroded headward along the newly created east-oriented flood flow movement and beheaded the south-oriented flood flow route it captured. Flood waters on the north end of the beheaded flood flow route reversed flow direction and the deep valley would again erode headward along the newly reversed flood flow route. Under certain conditions, which probably include bedrock characteristics, this zig zag process of deep valley erosion could continue for significant distances as seen along Meramec River.
Detailed map of Labadie Creek-Brush Creek drainage divide area
Figure 7: Detailed map of Labadie Creek-Brush Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 7 provides a detailed topographic map of the Labadie Creek-Brush Creek drainage divide area seen in less detail in figure 6 above. Gray Summit is located just south of the figure 7 center area. The Missouri Botanical Garden Arboretum is located south of Gray Summit near the figure 7 south edge. Brush Creek originates just west of section 18 and then flows in an east-northeast and east direction across the section 17 north half (near the word BOLES) to the figure 7 east edge. Just east of the Missouri Botanical Garden Arboretum in sections 16 and 15 the north end of a Meramec River meander can be seen. East of the figure 7 map area Brush Creek joins the Meramec River near the north end of another large meander. Little Fox Creek originates near the Trailer Park in section 4 and flows in an east-northeast direction to the figure 7 east edge (north half). East of figure 7 Little Fox Creek flows to Fox Creek, which then flows to the Meramec River. Labadie Creek originates in section 13 just west of the east-oriented Brush Creek headwaters in section 18 and flows in a northwest direction toward the figure 7 west edge and then turns to flow in a northeast direction to the figure 7 north edge (near where the two railroad lines cross). North of figure 7 Labadie Creek flows in a north direction to enter the Missouri River valley. Contour lines along the Labadie Creek-Brush Creek drainage divide in section 13 are very difficult to read although a spot elevation of 815 feet is provided and the drainage divide elevations appear to gradually drop as one proceeds in a north direction toward the Coleman School area where a spot elevation of 778 feet is provided. Continuing east along the drainage divide to Gray Summit elevations continue to drop until they are in the 670 foot range (see 677 foot spot elevation near highway interchange). The railroad uses a tunnel to cross the drainage divide at Gray Summit so spot elevations along the railroad do not reflect the drainage divide true elevation. Continuing in a northeast direction from Gray Summit into section 4, where Little Fox Creek originates, elevations rapidly rise as indicated by the spot elevation of 854 feet near the Trailer Park. By following the drainage divide elevations we have seen evidence for a major south-oriented flood flow channel, which supplied large volumes of flood water to what was once the actively eroding Meramec River valley. At that time the deep Missouri River valley to the north did not exist and flood waters were initially flowing on a topographic surface at least as high as the Gray Summit drainage divide elevation today. Headward erosion of the deep Missouri River valley beheaded the south-oriented flood flow channel and flood waters on the north end of the beheaded flood flow route reversed flow direction to erode the north-oriented Labadie Creek valley and its north-oriented tributary valleys.
Missouri River-Bourbeuse River drainage divide area
Figure 8: Missouri River-Bourbeuse River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 8 illustrates the Missouri River-Bourbeuse River drainage divide area located west of the figure 6 map area and includes overlap areas with figure 6. Washington is the larger town along the figure 8 northwest quadrant north edge and is located on the south side of the Missouri River valley. Note how the Missouri River changes from flowing in a southeast direction to flowing in a northeast direction( just east of Washington). Labadie Creek is the north-oriented Missouri River tributary flowing through the town of Labadie in the figure 8 northeast quadrant and originates west of Gray Summit, which is located near the figure 8 east center edge. Browns Branch flows in an east and north direction from the figure 8 center region before turning to flow in a northwest direction to join the Missouri River as a barbed tributary at Washington. Note how Browns Branch has several northwest-oriented tributaries. Union is the large town located in the figure 8 southwest quadrant. Dubois Creek is a northeast and north oriented Browns Branch tributary located north of Union. The Bourbeuse River meanders in a northeast direction from the figure 8 southwest corner to Union and then towards the figure 8 center before turning to meander in a south direction to the figure 8 south edge (just east of center). Birch Creek is the north-oriented tributary joining the south-oriented Bourbeuse River north of the south center edge. South of the figure 8 map area the Bourbeuse River joins the northeast-oriented Meramec River, which meanders in a north direction along the east margin of the figure 8 southeast quadrant. The figure 8 map evidence is complex, but the Brown Branch valley and its tributary valley orientations provide clues to help start unraveling the puzzle. The northwest-oriented Browns Branch valley segment and its northwest-oriented tributary valleys were eroded by reversals of southeast oriented flood flow routes which had been moving flood waters to what was then the newly eroded Meramec River valley. Headward erosion of the deep Bourbeuse River valley from the newly eroded and deep Meramec River valley eroded across and then along some of these flood flow routes. In doing so both southeast and northwest oriented oriented Bourbeuse River valley segments were eroded and flood waters on north ends of beheaded flood flow routes reversed flow direction to erode north-oriented tributary valleys to southeast-oriented Bourbeuse River valleys segments (e.g. Birch Creek). Next headward erosion of the deep northeast-oriented Missouri River valley captured the southeast-oriented flood flow and eroded headward along the southeast-oriented flood flow route. Flood waters on northwest ends of beheaded flood flow routes reversed flow direction to erode the northwest Brown Branch valley and its northwest-oriented tributary valleys.
Detailed map of Browns Branch-Bourbeuse River drainage divide area
Figure 9: Detailed map of Browns Branch-Bourbeuse River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 9 provides a detailed topographic map of the Browns Branch-Bourbeuse River drainage divide area seen in less detail in figure 8. Union is the town located at the figure 9 southwest corner. The Bourbeuse River meanders in a north-northwest, east-northeast, and southeast direction in the figure 9 south center area. The northwest-oriented tributary in section 19 is located in the northeast-oriented valley of what was once a large southeast and northeast oriented incised meander. Note how the abandoned meander and the present day larger meander surrounding it are defined by south-southeast or southeast and north-northwest or northwest valley segments, suggesting the deep Bourbeuse River valley first eroded headward along a southeast-oriented flood flow route and then beheaded an adjacent and parallel flood flow route and eroded headward next along a reversed flood flow route. Next the actively eroding deep valley captured another parallel flood flow route and eroded headward along the southeast-oriented flood flow channel before beheading another flood flow channel and eroding headward along the reversed flood flow route. Browns Branch originates near Bethlehem Ch. in the section 14 northeast quadrant (in figure 9 northwest quadrant) and flows in an east direction into section 7 where it turns to flow in a north direction to the figure 9 north edge. At first glance the Browns Branch-Bourbeuse River drainage divide appears to be a rather imposing high ridge. But let us start at Bethlehem Ch. and follow the drainage divide eastward. The map contour interval is 10 feet. Near Bethlehem Ch. a spot elevation reads 752 feet. Proceeding eastward along the drainage divide elevations drop to less than 680 feet near the section 13 southeast corner. At several points along the drainage divide in section 18 elevations are less than 680 feet, but in the section 18 southeast corner elevations rapidly rise again (see spot elevation of 735 feet in section 17 southwest corner). Near the figure 9 east edge there is a spot elevation of 790 feet on the drainage divide. While not seen in figure 9, if we were to continue west along the drainage divide west of the figure 9 map area we would soon encounter elevations greater than 800 feet. What do these elevations mean? Between the high points on the drainage divide is what remains of the large south-southeast oriented flood flow channel which supplied the flood water responsible for headward erosion of the deep Bourbeuse River valley. Headward erosion of the deep Missouri River valley north of the figure 9 map area beheaded the south-southeast oriented flood flow. Flood waters on the north end of the beheaded flood flow route reversed flow direction to erode the north-oriented Browns Branch valley. The reversed flood flow captured flood waters from yet to be beheaded flood flow routes west of the actively eroding Missouri River valley head and movement of that captured flood flow to the newly eroded north-oriented Browns Branch valley eroded the east-oriented Browns Branch headwaters valleys.
St Johns Creek-Bourbeuse River drainage divide area
Figure 10: St Johns Creek-Bourbeuse River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
- Figure 10 illustrates the St Johns Creek-Bourbeuse River drainage divide area located west and south of the figure 8 map area and includes overlap areas with figure 8. Union is the larger town located near the figure 10 northeast quadrant east edge. The Bourbeuse River meanders in a northeast direction from the figure 10 southwest corner to the small town of Greenstreet and then meanders in a southeast direction to cross the figure 10 south center edge. Noser Mill is a small town located along the Bourbeuse River a short distance downstream from Greenstreet. South of the south center edge the Bourbeuse River turns and then meanders in a northeast direction to the figure 10 east edge near Union. The Bourbeuse River flows to the Meramec River, which then flows to the Mississippi River. St Johns Creek originates near the figure 10 west center edge and flows in a northeast, east, and northeast direction to the figure 10 north edge (just east of center). North of figure 10 St Johns Creek flows in a north-northeast and northeast direction to join the southeast-oriented Missouri River just west of Washington. Note how St Johns Creek has southeast-oriented tributaries from the north and north-oriented tributaries from the south. The railroad line is located on or near the St Johns Creek-Bourbeuse River drainage divide, which is also the divide between the Missouri River and Meramec River drainage basins. While shallow through valleys are difficult to identify on the figure 10 map study of the drainage divide on more detailed topographic maps reveal through valleys linking north-oriented St Johns Creek tributary valleys with south-oriented Bourbeuse River tributary valleys. I will not illustrate the detailed topographic maps, but near the figure 10 west edge there are elevations exceeding 900 feet (on maps with contour intervals in feet) and then elevations drop to less than 800 feet north of Greenstreet. From the low point north of Greenstreet elevations rise somewhat until another low point with elevations below 800 feet is reached north of the Findley Landing Strip. From that eastern low point elevations quickly rise to more than 890 feet before decreasing in an east direction. These elevations define what was once a large south-oriented flood flow channel transporting flood waters to the actively eroding Bourbeuse River valley. The south-oriented flood flow channel was beheaded and reversed by headward erosion of the deep Missouri River valley and the reversed flood flow eroded the St Johns Creek valley and its north-oriented tributary valleys.
- The Bourbeuse River incised meanders are particularly noticeable and many, though not all, of the longer meander segments are oriented in southeast and northwest directions. A close look at drainage divides separating Bourbeuse River valleys on opposite sides of these incised meanders suggests flood waters once crossed those drainage divides. Figure 10a below provides a detailed topographic map of drainage divides separating Bourbeuse River valley segments in the Noser Mill region. The Bourbeuse River is meandering in a north direction in the figure 10a west half and is meandering in a southeast direction in the figure 10a east half. The map contour interval is 10 feet in the north and 20 feet in the south. Elevations in section 19 along the drainage divide between the north-oriented Bourbeuse River to the west and the southeast-oriented Bourbeuse to the east drop to between 630 and 640 feet. Contour lines along the Bourbeuse River channel just west of this drainage divide low area read 620 feet and just east of the drainage divide low area the contour lines adjacent to the Bourbeuse River channel read either 590 feet or 600 feet. Follow the drainage divide north and there is a spot elevation of 736 feet and follow the drainage south and there is a spot elevation of 850 feet near the figure 10 south center edge. In other words there is a deep through valley linking valley segments where the Bourbeuse River is today flowing in opposite directions. The through valley was eroded at a time when the deep Bourbeuse River valley was eroding headward to capture the immense south-oriented flood flow. A similar through valley can be seen along the line between sections 13 and 18 and is located between a northwest and southwest oriented Bourbeuse River valley segment and an east and north oriented Bourbeuse River valley segment. The through valley floor elevation is between 650 and 660 feet in elevation and elevations along the drainage divide to the east rise to 736 feet in section 18 and to the west rise to more than 730 feet in the section 13 southwest corner. Another somewhat similar through valley can be seen in the section 20 south half linking a west-oriented Bourbeuse River valley segment with a southeast-oriented tributary valley draining to a northeast-oriented oriented Bourbeuse River valley segment. I will not try to decipher flood flow movements responsible for these through valleys and the present day Bourbeuse River valley segments, however the through valleys provide evidence the deep Bourbeuse River valley eroded headward along and across what was once a complex of flood flow channels.
Detailed map of Bourbeuse River-Bourbeuse River drainage divides near Noser Mill
Figure 10a: Detailed map of Bourbeuse Tiver-Bourbeuse River drainage divides near Noser Mill. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Additional information and sources of maps studied
This essay has provided only a sample of the detailed topographic map evidence supporting the flood erosion interpretation. Many additional illustrations could be provided. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of available data. Maps used in this study were created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.
Missouri River drainage basin landform origins research project 
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