A geomorphic history based on topographic map evidence
The drainage divide between Elk Creek and Boxelder Creek originates in the western South Dakota Black Hills and continues east of the Black Hills to the Cheyenne River valley. Although detailed topographic maps of the Elk Creek-Boxelder Creek drainage divide area have been available for more than fifty years detailed map evidence has not previously been used to interpret the region’s geomorphic history. The interpretation provided here is based entirely on topographic map evidence. The Elk Creek-Boxelder Creek drainage divide area is interpreted to have been eroded during immense southeast-oriented flood events, the first of which flowed on a topographic surface at least as high as the highest points in the present-day drainage divide area today, although the Black Hills area may have been uplifted during and/or following the flood. Flood flow across the Elk Creek-Boxelder Creek drainage divide area in the Black Hills ended when headward erosion of the Elk Creek valley captured all southeast-oriented flood flow to the Boxelder Creek drainage basin.
- The purpose of this essay is to use topographic map interpretation methods to explore western South Dakota Elk Creek-Boxelder Creek drainage divide area landform origins. 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 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 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 similar essays is a thick North American ice sheet, comparable in thickness to the present day Antarctic ice sheet, occupied approximately the North American region usually recognized to have been glaciated and through its weight and erosive actions created a “deep” North American “hole”, 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 Elk Creek-Boxelder Creek drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.
Elk Creek-Boxelder Creek drainage divide area general location map
Figure 1: Elk Creek-Boxelder Creek drainage divide area general location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.
Figure 1 provides a general location map for the Elk Creek-Boxelder Creek drainage divide area. South Dakota is the state occupying the eastern two-thirds of figure 1. Wyoming is the state west of South Dakota. The Black Hills region is a domal uplift with an exposed core of Precambrian rocks and stands significantly higher than the surrounding plains region. Major drainage routes shown on figure 1 are the Cheyenne River and its tributary Belle Fourche River. The Cheyenne River originates in Wyoming west of the figure 1 map area and flows northeast and southeast to go around the Black Hills south end and then turns northeast to flow between the Black Hills and the Badlands National Park. The Belle Fourche River also originates in Wyoming west of the figure 1 map and flows northeast to go around the Black Hills north end before flowing southeast and east-northeast to reach the northeast-oriented Cheyenne River. Elk Creek originates in the Black Hills area south of the town of Deadwood, South Dakota and flows generally in a southeast direction to Piedmont, South Dakota and north of New Underwood turns northeast to flow to the northeast-oriented Cheyenne River. Boxelder Creek originates west of Nemo, South Dakota near the Elk Creek headwaters area and flows southeast by Nemo, Black Hawk, Ellsworth Air Force Base, and New Underwood before flowing to the Cheyenne River. Other Black Hills region drainage divide essays can be found under Black Hills region on the sidebar category list. This essay interprets Elk Creek-Boxelder Creek drainage divide area landform origins in the context of an immense southeast oriented flood that flowed across the entire figure 1 map area and that was systematically captured by headward erosion of deep northeast-oriented valleys, which diverted flood waters further and further northeast and north. The source of the southeast-oriented flood water cannot be determined from evidence presented here. However, based on evidence presented in numerous other Missouri River drainage basin landform origins research project essays published on this website the floods occurred before and/or while the Black Hills area was being uplifted and the flood waters can be traced headward to a North American ice sheet location. Rapid melting of a thick North American ice sheet located in a deep “hole” would explain the flood water source and also why deep valleys eroded west and southwest to capture southeast-oriented flood waters to divert flood waters further and further northeast and north into space in the deep “hole” the rapidly melting ice sheet had once occupied. In addition, presence of a thick North American ice sheet in a deep “hole” north and east of the Black Hills might explain crustal warping that uplifted the Black Hills dome during or even after an immense southeast-oriented flood. Uplift of the Black Hills dome may have been accelerated by crustal unloading as flood waters deeply eroded the Black Hills region and removed overlying sedimentary layers.
Elk Creek-Boxelder Creek drainage divide area detailed location map
Figure 2: Elk Creek-Boxelder Creek drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 2 provides a slightly more detailed Elk Creek-Boxelder Creek drainage divide area location map. Lawrence County, Pennington County, and Meade County are all located in western South Dakota. The green areas represent Black Hills National Forest lands and are generally located in higher elevation Black Hills areas. The Belle Fourche River flows east and southeast from Belle Fourche, South Dakota (located in the figure 2 northwest corner along the north edge) before turning east-northeast to join the northeast-oriented Cheyenne River in the figure 2 northeast corner. The northeast-oriented Cheyenne River is located west of the Badlands National Park (located in the figure 2 southeast corner) and flows northeast to join the Belle Fourche River in the figure 2 northeast corner. Elk Creek originates west of Custer Peak (located in southern Lawrence County south of Deadwood) and flows northeast, east, northeast, southeast to reach Piedmont (located northwest of Rapid City). From Piedmont Elk Creek flows southeast before turning northeast and east to reach the Cheyenne River. Boxelder Creek originates at Custer Peak and south of Custer Peak and flows southeast to Black Hawk (just northwest of Rapid City) and then south of Ellsworth Air Force Base to New Underwood and then to the Cheyenne River. South of Boxelder Creek is Rapid Creek, which roughly parallels Boxelder Creek and which flows through Rapid City, South Dakota. Figure 2 shows few tributary streams in the Elk Creek-Boxelder Creek drainage divide area and those will have to be seen on more detailed maps below. However, figure 2 does show numerous southeast-oriented Belle Fourche River, Cheyenne River, and Rapid Creek tributaries and several northwest-oriented Cheyenne River tributaries. The southeast-northwest tributary orientation is evidence the major east- and northeast-oriented valleys eroded headward across multiple southeast-oriented flood flow routes or channels, such as might be found in a southeast-oriented anastomosing channel complex. Northwest-oriented tributary valleys were eroded by reversed flow on the northwest ends of beheaded southeast-oriented flood flow routes. Often reversed flow on these beheaded flood flow routes captured flood flow from yet to be beheaded southeast-oriented flood flow routes further to the south or southwest. Such captured flood water helped erode significant northwest-oriented valleys.
Western end of the Elk Creek-Boxelder Creek drainage divide area
Figure 3: Western end of the Elk Creek-Boxelder Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 3 illustrates the Elk Creek-Boxelder Creek drainage divide area west end. Elk Creek originates in the figure 3 west center just west of Custer Peak and flows northeast to Brownsville and Roubaix into the figure 3 northeast corner where Elk Creek turns southeast to flow to the figure 3 east edge. An Elk Creek tributary important in the figure 6 discussion below is Little Elk Creek, which is located in the figure 3 east center. North Boxelder Creek originates southeast of Custer Peak and flows southeast, northeast, southeast and northeast to Benchmark where Boxelder Creek turns southeast to flow through Greenwood and Nemo (figure 3 southeast corner). Major Boxelder Creek tributaries from the north include southeast-oriented Corral Creek and Hay Creek both located in the figure 3 center area. The North Fork Rapid Creek flows southeast in the figure 6 southwest corner. Bear Butte Creek is the east and northeast oriented stream located north of Brownsville and flowing to the figure 6 north edge (center west). Many figure 6 streams are southeast-oriented or have southeast-oriented segments. Also through valleys link headwater areas of south and southeast-oriented streams with north and northwest-oriented valleys, suggesting water once crossed present day drainage divides. For example, southeast-oriented headwaters of North Boxelder Creek are linked by a high level through valley to the northeast-oriented Elk Creek valley (illustrated in more detail in figure 4 below). While the Custer Peak area stands high above the surrounding region today, this high level through valley is evidence southeast-oriented water once flowed from what is today the Elk Creek drainage basin to what is today the Boxelder Creek drainage basin on topographic surface at least as high as Custer Peak today (although Black Hills region uplift may not have yet occurred at that time). The southeast-orientation of present day streams is evidence a southeast-oriented anastomosing channel complex once crossed this Black Hills upland area and was subsequently dismembered by headward erosion of deep northeast-oriented valleys as the Black Hills area was uplifted relative to the surrounding plains region. Headward erosion of deep southeast-oriented valleys also captured flood flow and diverted water to new channels and in new directions. In summary figure 3 drainage pattern evidence can be best explained in the context of an immense southeast-oriented flood, which crossed the entire figure 3 map area and which flowed in what was probably an ever-changing southeast-oriented anastomosing channel complex as the Black Hills region was being uplifted. Detailed maps below will illustrate how the southeast-oriented anastomosing channel complex was dismembered.
Elk Creek-North Boxelder Creek drainage divide at Custer Peak
Figure 4: Elk Creek-North Boxelder Creek drainage divide at Custer Peak. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 4 illustrates the Elk Creek-Boxelder Creek drainage divide area at Custer Peak. Custer Peak is located in the figure 4 center. Northeast-oriented Elk Creek headwaters are located in the northeast-oriented valley just west of Custer Peak. The southeast-oriented North Boxelder Creek valley originates at the pass used by the road going over Custer Peak and North Boxelder Creek flows southeast to the abandoned Boxelder School location and then northeast to the figure 4 east edge. Headwaters of northeast-oriented Whitewood Creek are located in the figure 4 northwest corner (Whitewood Creek flows to the southeast-oriented Belle Fourche River). A through valley linking the northwest-oriented East Spearfish Creek valley with the southeast-oriented North Fork Rapid Creek valley is located in the figure 4 southeast corner. A through valley linking the north-oriented Whitewood Creek valley and the northwest-oriented East Spearfish Creek-southeast-oriented North Fork Rapid Creek through valley is located along the figure 4 west edge. A through valley linking the northeast-oriented Elk Creek valley with the northwest-oriented East Spearfish Creek-southeast-oriented North Fork Rapid Creek through valley is located just west and southwest of Custer Peak. The through valleys were eroded as components of a large-scale anastomosing channel complex that carried flood water across what is today the Black Hills upland surface. Food waters were generally moving to deep southeast-oriented valleys eroding headward into what was probably the rising Black Hills upland region, one of which was the Rapid Creek-North Fork Rapid Creek valley. Another deep valley was the Elk Creek valley and the through valley link between the North Fork Rapid Creek and Elk Creek valleys is evidence that at one time flood water moving southeast from what is today the Spearfish Creek drainage basin split in this figure 4 region, with some water going northeast to erode the Elk Creek valley and some water going southeast to erode the Rapid Creek-North Fork Rapid Creek valley. Custer Peak stands approximately 800 feet higher than the Elk Creek valley to the west and more than 1000 feet higher than the abandoned Boxelder School location to the southeast. The height of Custer Peak above the surrounding figure 4 region provides evidence flood waters removed hundreds of feet of rock from this Black Hills upland area. The southeast-oriented basin carved into the Custer Peak mountain mass is an abandoned headcut, eroded by southeast-oriented flood water that was eroding a deep southeast-oriented valley headward. Flood flow over the Custer Peak mountain mass was beheaded by headward erosion of a deep northeast-oriented Elk Creek valley, which was eroding southeast into the region. Deep flood erosion of what is today the Black Hills uplifted area may have been at least in part responsible for Black Hills uplift as southeast-oriented flood waters were crossing the figure 5 map area.
Elk Creek-Hay Creek drainage divide area
Figure 5: Elk Creek-Hay Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 5 illustrates the Elk Creek-Hay Creek drainage divide area located east and southeast of Roubaix, South Dakota (located on the figure 5 west edge center north-refer to figure 3 for location). Elk Creek flows from the figure 5 west edge (center north) northeast to the figure 5 northeast corner. Hay Creek headwaters located in the figure 5 west center flow northeast before turning southeast to flow through the figure 5 south center. Headward erosion of a deep northeast-oriented Elk Creek valley beheaded southeast oriented flood flow to the Hay Creek valley. The figure 5 map area does not have any high monadnocks like Custer Peak and the amount of rock material removed from this region cannot easily be determined. East and northeast-oriented hogbacks are located along the figure 5 northeast third and suggest a thick sedimentary rock cover was removed from the entire figure 5 region. A close look at figure 5 reveals a maze of through valleys linking the various drainage networks. For example a north-south through valley links the Elk Creek valley in the north with the southeast oriented Hay Creek valley a short distance downstream from Reausaw Lake (figure 5 south center). Also reaching Hay Creek at the same point is a northwest-southeast oriented through valley that also links the Elk Creek valley and the Hay Creek valley. Today a northwest-oriented Elk Creek tributary occupies the northwest of that valley while a southeast oriented Hay Creek tributary occupies the southeast end. Further east the southeast- and northeast-oriented Meadow Creek valley (northeast corner area) is linked by a north-south through valley to the southeast-oriented Elk Creek valley. The east-oriented Little Elk Creek valley is connected by a through valley to the north-south through valley linking Meadow Creek with Hay Creek . These through valleys and many others like them provide evidence headward erosion of the deep Elk Creek valley and Elk Creek tributary valleys (Meadow Creek and Little Elk Creek are Elk Creek tributaries) beheaded southeast-oriented flood flow routes to what was then an actively eroding Hay Creek valley and diverted the water north and northeast to the newly eroded Elk Creek valley. East-oriented headwaters of Little Elk Creek are located in the figure 5 southeast quadrant near the east edge.
Little Elk Creek-Boxelder Creek drainage divide area north of Nemo, South Dakota
Figure 6: Little Elk Creek-Boxelder Creek drainage divide area north of Nemo, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 6 illustrates the Little Elk Creek-Boxelder Creek drainage divide area north of Nemo, South Dakota (located in the figure 3 southeast corner) and the northwest corner of figure 6 overlaps with the southeast corner of figure 5. Boxelder Creek flows southeast from the figure 6 west edge center to Nemo located along the figure 6 south edge center. Little Elk Creek flows southeast in Little Elk Canyon (figure 6 north center) to the Dalton Lake area where it turns northeast to flow to the figure 6 east edge. Wilson Draw drains southeast from an escarpment-surrounded basin in the figure 6 northwest corner with water joining Boxelder Creek at Nemo. The escarpment-surrounded basin is an abandoned headcut eroded by southeast oriented flood waters. Another prominent southeast oriented abandoned headcut is located in the figure 6 north center just south of the words Elk Canyon. An unnamed Little Elk Creek tributary flows from that figure 6 north center abandoned headcut, and northwest of the abandoned headcut is a southeast and northeast-oriented Little Elk Creek tributary flowing in a deep valley. That deep valley is linked by a through valley with southeast-oriented Wilson Draw and provides evidence as to how much erosion the flood waters accomplished. Southeast-oriented flood flow responsible for eroding the Wilson Draw headcut northwest was captured by headward erosion of the deeper Little Elk Canyon and a northeast-oriented Little Elk Creek tributary valley (seen immediately northwest of the abandoned headcut). Refer back to figure 5 to see how that tributary valley is linked to the north-south through valley linking the Meadow Creek valley with the Hay Creek valley and also with the Little Elk Creek headwaters valley. Those through valleys were eroded deeper than the southeast-oriented flood flow route that eroded the Wilson Draw headcut. One of the most striking figure 6 landscape features is the anastomosing valley complex and northwest-southeast oriented streamlined hills located in the figure 6 center. That valley complex and streamlined hills provide strong evidence of large quantities of southeast-oriented flood water flowing to what was then the actively eroding the Boxelder Creek valley. That southeast-oriented flood flow was subsequently captured by headward erosion of the Little Elk Creek valley and the flood waters were diverted to what was then the actively eroding Elk Creek valley.
South Stagebarn Canyon-Boxelder Creek drainage divide area east of Nemo, South Dakota
Figure 7: South Stagebarn Canyon-Boxelder Creek drainage divide area east of Nemo, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 7 provides a map of the Stagebarn Canyon-Boxelder Creek drainage divide area located southeast of the figure 6 map area and includes overlap areas with figure 6. South Stagebarn Creek flows southeast across the figure 7 north center and then turns east before turning southeast to flow to the figure 7 east enter edge and then turning northeast to flow to Elk Creek (see figure 7a below for a location map). Boxelder Creek flows south-southeast from Nemo in the figure 7 northwest corner to the figure 7 south edge. A well-defined north-northeast to south-southwest oriented through valley links South Stagebarn Canyon with the Boxelder Creek valley. Today that through valley is drained by a southeast and northeast-oriented South Stagebarn Creek tributary at the north end and by a south-southwest oriented Boxelder Creek tributary at the south end. A northwest-southeast through valley in the figure 7 north center links Stagebarn Canyon with the head of the southeast and northwest oriented South Stagebarn Creek tributary. The through valleys provide evidence of anastomosing south-oriented flood flow channels with flood waters being captured by headward erosion of the deep Elk Creek-Stagebarn Creek-South Stagebarn Creek valley. In the figure 7 northwest quadrant between the Boxelder Creek valley and South Stagebarn Canyon is an escarpment-surrounded basin drained by a southeast-oriented stream to southeast-oriented Erskine Gulch. The escarpment-surrounded basin is another abandoned headcut, which was abandoned when headward erosion of the South Stagebarn Creek valley eroded headward into the region and captured the southeast-oriented flood flow that had been eroding the headcut northwest. An east-southeast oriented through valley northeast of Nemo in figure 6 was eroded headward from the actively eroding southeast-oriented South Stagebarn Creek valley. Subsequently headward of the Boxelder Creek valley captured south-oriented flood flow to that valley (resulting in the present day through valley). The height of the ridges surrounding the abandoned headcut provide a minimum measure of the amount of erosion flood waters accomplished and how deep the headcut was.
Figure 7a: Location map for South Stagebarn Canyon discussed in figure 7 above and illustrates the region between figure 3 above and figure 8 below. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Elk Creek-Boxelder Creek drainage divide area north of Rapid City, South Dakota
Figure 8: Elk Creek-Boxelder Creek drainage divide area north of Rapid City, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 8 illustrates the Elk Creek-Boxelder Creek drainage divide east of the Black Hills upland area. Elk Creek flows east-northeast across the figure 8 northwest quadrant and southeast in the figure 8 northeast quadrant. Boxelder Creek flows east through Blackhawk, South Dakota in the figure 8 southwest quadrant and turns southeast to flow south of Ellsworth Air Force Base in the figure 8 southeast quadrant. Northwest-southeast oriented hogback ridges parallel the Black Hills upland slope. For example the northwest-southeast oriented highway and railroad are located in a through valley between a northeast-dipping hogback ridge and the Black Hills upland northeast-facing slope. That through valley today is drained in the south by east-oriented Boxelder Creek and in the north by east-oriented Elk Creek. Yet at one time water flowed in the through valley to erode it. It is hard to explain the Elk Creek and Boxelder Creek water gaps carved the northeast-dipping hogback ridge unless they were both cut at approximately the same time and at a time when water was flowing southeast in what is now the through valley. The southeast-oriented flood flow in that valley was subsequently beheaded by headward erosion of the Elk Creek valley. In other words, the valley is evidence of anastomosing flood flow channels, although perhaps of a different nature than the anastomosing flood flow channels seen further to the west. The southeast-oriented Elk Creek and Boxelder Creek valley orientations is also evidence of southeast-oriented flood flow across the figure 8 map region. Flood erosion of this figure 8 map region was intense, but evidence visible in figure 8 is not adequate to determine how much material was removed. And more detailed maps are needed to best understand the drainage history.
Elk Creek-Boxelder Creek drainage divide area north of New Underwood, South Dakota
Figure 9: Elk Creek-Boxelder Creek drainage divide area north of New Underwood, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 9 illustrates the Elk Creek-Boxelder Creek drainage divide area east of Ellsworth Air Force Base. East-oriented Elk Creek can be seen along the figure 9 north edge. East-southeast oriented Boxelder Creek is seen in the figure 9 southwest corner. New Underwood, South Dakota is located just south of the highway interchange located in the figure 9 south center. The Elk Creek-Boxelder Creek drainage divide is the east-west ridge separating what are today the large east-oriented Elk Creek valley from the large east-oriented Boxelder Creek valley. Note how the Boxelder Creek valley north wall is a relatively smooth south-oriented sloping erosion surface now drained by southeast-oriented valleys. In contrast the north facing Elk Creek valley wall has many shallow north oriented Elk Creek tributary valleys. What has happened is first a large east-oriented Boxelder Creek headcut eroded west into a topographic surface higher than any figure 9 elevations today to capture southeast-oriented flood flow moving across the figure 9 region. The southeast-oriented flood flow then began to erode the newly eroded and deep Boxelder Creek valley north wall and eroded the relatively smooth southeast-oriented erosion surface. Shortly thereafter the large Elk Creek valley headcut eroded west just to the north of the newly eroded Boxelder Creek valley and beheaded the southeast-oriented flood flow moving to the Boxelder Creek valley. Headward erosion of the Elk Creek valley headcut occurred by eroding valleys headward from the actively eroding valley head to capture yet to be beheaded southeast-oriented flood flow. The south valley wall was eroded by north- and northeast-valleys that eroded south and southwest to capture yet to be beheaded southeast-oriented flood flow. For that reason the north-facing Elk Creek valley wall was never eroded by southeast-oriented flood flow, but was instead eroded by captured flood flow moving north to the actively eroding Elk Creek valley head. The south-facing Elk Creek valley wall is a smooth southeast-sloping erosion similar to the south-facing Boxelder Creek valley wall and is illustrated in the Belle Fourche River-Elk Creek drainage divide essay. The relatively smooth southeast-sloping erosion surfaces have sometimes been considered stream terraces, because valleys have been eroded into them. The deeper valleys eroded into the erosion surfaces are evidence that headward erosion of the large Boxelder Creek and Elk Creek valley headcuts occurred shortly before headward erosion of the deep Cheyenne River valley. Prior to headward erosion of the deep Cheyenne River flood waters were flowing east across what is now the Badlands National Park area to what was then an actively eroding and deep White River valley. Headward erosion of the deep Cheyenne River valley captured the southeast-oriented flood flow and also was responsible for eroding the Boxelder Creek valley deeper as Elk Creek valley headward erosion was still beheading the southeast-oriented flood flow.
Elk Creek-Boxelder Creek drainage divide area near the Cheyenne River
Figure 10 illustrates using greatly reduced maps the Elk Creek-Boxelder Creek drainage divide area immediately west of the Cheyenne River. The Cheyenne River is located in the north-oriented valley located in the figure 10 southeast and northeast quadrants. Elk Creek is located in the northeast and east-oriented valley in the northwest and northeast figure 10 quadrants. Boxelder Creek is located in the southeast-oriented valley in the figure 10 southwest quadrant. The town located where the highway crosses the Cheyenne River valley is Wasta, South Dakota. East of the Cheyenne River the highway is located in the northwest-oriented Bull Creek valley and just southeast of the figure 10 southeast corner is the town of Wall, South Dakota. The Cheyenne River-Bad River drainage divide essay describes evidence east of the Cheyenne River and north of the northwest-oriented Bull Creek valley and can be found under Bad River on the sidebar category list. The Cheyenne River-White River drainage divide essay describes the area east of the Cheyenne River valley and south of the Bull Creek valley and can be found under White River on the sidebar category list. The southeast-oriented Boxelder Creek valley is headed almost directly toward what are today two large southeast-oriented abandoned headcuts carved into what was once the deep northeast and east-oriented White River valley northwest wall (today the Sage Creek Basin is in the Badlands National Park). Headward erosion of the deep Cheyenne River valley captured southeast-oriented flood flow moving in what is today the Boxelder Creek valley, beheading flood flow to what had been the actively eroding Sage Creek and Scenic Basin headcut faces. Reversed flood flow was responsible for eroding the northwest-oriented Cheyenne River tributary valleys. Prior to headward erosion of the deep Cheyenne River valley southeast-oriented flood flow from what is today the Elk Creek drainage basin was flowing southeast in what is today the northwest-oriented Bull Creek area (southeast-oriented Hawk Canyon used by the highway west of the Cheyenne River and southeast-oriented Pars Draw are located on the southeast-oriented flow route those flood waters used). Headward erosion of the deep Cheyenne River valley enabled an east-oriented tributary valley to erode west to capture southeast-oriented flood flow. That tributary valley then turned to erode southwest across the southeast-oriented flood route carrying water to the Pars Draw and Hawk Canyon area and southeast along the Bull Creek alignment. The deep north-oriented Cheyenne River valley eroded south to capture the large volumes of southeast-oriented flood flow moving along valleys like the rapidly eroding Elk Creek and Boxelder Creek valleys.
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.