Whitewood Creek-Bear Butte Creek drainage divide area landform origins, Black Hills region, western South Dakota, USA

Authors

A geomorphic history based on topographic map evidence

Abstract:

The drainage divide between Whitewood Creek and Bear Butte Creek is located in the South Dakota Black Hills, USA. Although detailed topographic maps of the Whitewood Creek-Bear Butte 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 Whitewood Creek-Bear Butte 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 Whitewood Creek-Bear Butte Creek drainage divide area ended when headward erosion of the deep Whitewood Creek valley captured all southeast-oriented flood flow.

Preface:

The following interpretation of detailed topographic map evidence is provided as evidence in the Missouri River drainage basin landform origins research project, which is compiling similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with and within certain adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored geomorphology paradigm, which is briefly described in the introduction below. Project essays are listed on the sidebar category list under their appropriate Missouri River tributary drainage basin, Missouri River segment drainage basin (by state), and/or state in which the Missouri River drainage basin is located.

Introduction:

  • The purpose of this essay is to use topographic map interpretation methods to explore South Dakota Whitewood Creek-Bear Butte 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 Whitewood Creek-Bear Butte Creek drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Whitewood Creek-Bear Butte Creek drainage divide area location map

Figure 1: Whitewood Creek-Bear Butte Creek 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 provides a location map for the Whitewood Creek-Bear Butte Creek drainage divide area. Lawrence County and Meade County are located in western South Dakota. The green areas represent Black Hills National Forest lands and roughly encompass the region referred to here as the Black Hills uplift region. Whitewood Creek originates east of Cheyenne Crossing in southern Lawrence County and flows northeast through Deadwood and Whitewood, South Dakota to join the southeast-oriented Belle Fourche River west of Vale, South Dakota. Bear Butte Creek originates east of the Whitewood Creek headwaters (just north of Elk Creek) and flows northeast through Sturgis and Bear Butte to join the southeast-oriented Belle Fourche River near Volunteer, South Dakota. Note southeast-oriented Bear Butte Creek tributaries between Sturgis and Volunteer. Other essays describing Black Hills region drainage divide areas can be found under Black Hills region on the sidebar category list. The Black Hills uplift region is a domal uplift with an exposed core of Precambrian rocks and stands significantly higher than the surrounding plains region. This essay interprets the origin of Whitewood Creek-Bear Butte Creek drainage divide area landforms in the context of an immense southeast oriented flood that flowed across the entire figure 1 map area and 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 the collective evidence of numerous other Missouri River drainage basin landform origins research project essays (published on this website) the floods occurred before or while the Black Hills area was being uplifted and 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 and diverted 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 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.

Whitewood Creek-Bear Butte Creek drainage divide area north of Black Hills

Figure 2: Whitewood Creek-Bear Butte Creek drainage divide area north of Black Hills. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 illustrates the Whitewood Creek-Bear Butte Creek drainage divide area north of the Black Hills uplift area, although some of the northwest-southeast oriented ridges are hogback ridges surrounding the raised Black Hills higher elevation areas to the southwest. Whitewood Creek flows northeast across the figure 2 northwest corner to join the southeast-oriented Belle Fourche River, which flows from the figure 2 northwest corner to the figure 2 southeast quadrant and east edge. Northeast-oriented Bear Butte Creek is located in the figure 2 southeast corner. The northeast and east-southeast-oriented stream in the figure 2 south center is Spring Creek, which is a Bear Butte Creek tributary. Ninemile Creek is the northeast-oriented Belle Fourche River located midway between Whitewood Creek and Bear Butte Creek and northeast-oriented Dry Creek flows to the Belle Fourche River midway between Ninemile Creek and Bear Butte Creek. Note how northeast-oriented Bear Butte Creek has numerous southeast-oriented tributaries and northeast-oriented Ninemile Creek has numerous southeast-oriented and northwest-oriented tributaries. This northwest-southeast orientation of tributaries to the major northeast-oriented valleys suggests the northeast-oriented valleys were eroded across multiple channels of southeast-oriented flood flow, such as might be found in a southeast-oriented anastomosing channel complex. The southeast-oriented tributary valleys were eroded along southeast-oriented channels from walls of the newly eroded northeast-oriented valleys, which had captured the southeast-oriented flood flow. The northwest-oriented tributary valleys were eroded by flood waters on the northwest ends of the beheaded flood flow channels. Flood waters on the northwest ends of those beheaded flood flow channels reversed flow direction to flow northwest to the newly eroded and deeper northeast-oriented valleys. Often these flow reversals captured flood waters from yet to be beheaded flood flow further to the south or southwest. Such captures sometimes provided large amounts of water to help erode a significant northwest-oriented tributary valley. Evidence for this beheading of flood flow channels will also be seen along the Whitewood Creek-Bear Butte Creek drainage divide further to the southwest.

Whitewood Creek-Bear Butte Creek drainage divide area north of Sturgis, South Dakota

Figure 3: Whitewood Creek-Bear Butte Creek drainage divide area north of Sturgis, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Whitewood Creek-Bear Butte Creek drainage divide area southwest of the figure 2 map area and includes overlap areas with figure 2. Whitewood Creek flows from Crook City in the figure 2 southwest corner north and northeast into the figure 3 northwest quadrant and then to the figure 2 north edge. Bear Butte Creek flows northeast from the Fort Meade Reservation to the figure 3 west edge center. Spring Creek flows northeast through the figure 3 center area and turns east-southeast to join Bear Butte Creek east of figure 3. Bear Butte is usually considered to be an igneous intrusion, now standing high after erosion removed the surrounding sedimentary rock. Again, northwest-southeast oriented ridges are hogback ridges associated with the Black Hills domal uplift. Note southeast-oriented Spring Creek tributaries and also southeast-oriented Bear Butte Creek and Whitewood Creek tributaries. These tributaries provide additional evidence the northeast-oriented valleys eroded headward across multiple southeast-oriented flood flow routes, such as might be found in a southeast-oriented anastomosing channel complex. Spring Creek headwaters provide further evidence supporting this anastomosing channel complex interpretation. Spring Creek originates in the figure 3 southwest quadrant east of Whitewood (almost on the edge of the north-oriented Whitewood Creek valley) and flow southeast before turning northeast to flow through a water gap carved across the northwest-southeast oriented ridge (on which Oyster Mountain is located). That water gap and the northwest-southeast oriented through valley southwest of Oyster Mountain provide evidence that at one time multiple flow routes carried flood water southeast and east from what is now the north-oriented Whitewood Creek drainage basin to what was then probably the newly eroded northeast-oriented Bear Butte Creek valley.

Whitewood Creek-Bear Butte Creek drainage divide area south of Sturgis, South Dakota

Figure 4: Whitewood Creek-Bear Butte Creek drainage divide area south of Sturgis, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Whitewood Creek-Bear Butte Creek drainage divide area south of the figure 3 map area and includes overlap areas with figure 3. Whitewood Creek flows from the figure 4 southwest corner through Kirk, Pluma, and Deadwood to reach Crook City near the figure 4 north center edge. Bear Butte Creek flows northeast from the figure 4 south center edge and then north before turning northeast to flow through Boulder Canyon and then east to Sturgis, South Dakota. Note northwest-oriented tributaries to northeast-oriented Whitewood Creek and southeast-oriented tributaries to Bear Butte Creek. Through valleys (some are better seen on more detailed maps) cross all of the major drainage divides. To some extent the drainage orientation is a reflection of underlying geologic structures, however the drainage orientation and the high level through valleys also are relics from multiple southeast-oriented flood flow channels, such as might be found in an anastomosing channel complex, which flowed across the figure 4 map region and were captured by headward erosion of deep northeast-oriented valleys. The deep northeast-oriented Bear Butte Creek valley eroded headward first (in the figure 4 area) and headward erosion of the deep Whitewood Creek valley followed shortly after. At that time the Black Hills did not stand high above the surrounding plains region. Today Strawberry Ridge in the figure 4 southwest quadrant stands almost 1000 meters higher than the elevation at Volunteer, South Dakota, where Bear Butte Creek joins the Belle Fourche River. Flood erosion had yet to remove several hundred meters of sedimentary cover from the surrounding plains region and uplift of the Black Hills dome area was probably just beginning. Several prominent through valleys link the two northeast-oriented drainage basins. One set of through valleys is located west and northwest of Boulder Canyon, which figure 5 below illustrates in detail. Another prominent through valley is located in Boulder Creek-Mountain Meadow area. Figure 6 below illustrates the Meadow Mountain-Boulder Creek through valley area in detail.

Detailed map of Whitewood Creek-Bear Butte Creek drainage divide northwest of Boulder Park

Figure 5: Detailed map of Whitewood Creek-Bear Butte Creek drainage divide northwest of Boulder Park. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates in detail through valleys west and northwest of Boulder Canyon. Bear Butte Creek flows northeast through Boulder Canyon located in the figure 5 southeast corner. Whitewood Creek flows northeast across the figure 5 northwest corner. Boulder Canyon has been eroded through a prominent northeast dipping hogback ridge and the through valley extending northwest from Boulder Park definitely is related to the underlying geologic structure. However, the through valley also was eroded and that erosion most likely was done by southeast-oriented flood water followed by reversed flood flow northwest of the present-day Whitewood Creek-Bear Butte Creek drainage divide. Headward erosion of the deep Bear Butte Creek valley through Boulder Canyon occurred first and captured southeast-oriented flood flow southwest of Boulder Canyon. One southeast-oriented flood flow channel had begun to erode what is today the northwest-southeast oriented through valley located northwest of Boulder Park and east of Crook Mountain, although this channel never eroded the northwest end of the through valley lower than the present day drainage divide level. Another southeast-oriented flow channel began to erode the valley now used by northwest-oriented Sandy Creek (located in figure 5 southwest of Crook Mountain), although this southeast-oriented channel never eroded the Sandy Creek valley deeper than the present day drainage divides with the northwest-southeast oriented through valley east of Crook Mountain (drainage divides are located southeast of Crook Mountain). Headward erosion of the deep northeast-oriented Whitewood Creek valley next beheaded southeast-oriented flood flow in the channel flowing on the northwest-southeast oriented through valley alignment east of Crook Mountain while yet to be beheaded southeast-oriented flood flow continued to move southeast along the Sandy Creek valley alignment. Flood flow on the northwest end of the beheaded flood flow channel east of Crook Mountain reversed flow direction and began to flow northwest to the newly eroded northeast-oriented Whitewood Creek valley (and created the drainage divide in the northwest-southeast-oriented through valley). Some of the yet to be beheaded flood flow moving southeast on the Sandy Creek alignment was captured south of Crook Mountain and diverted northeast into the reversed flood flow end of the through valley and helped erode the northwest-oriented valley northwest of the drainage divide, while other yet to be beheaded flood flow continued to flow to what was then the actively eroding northeast-oriented Bear Butte Creek valley.

Detailed map of Whitewood Creek-Bear Butte Creek drainage divide west of Boulder Park

Figure 6: Detailed map of Whitewood Creek-Bear Butte Creek drainage divide west of Boulder Park. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates in detail the Mountain Meadow-Boulder Creek through valley south of figure 5 and seen in less detail in figure 4. Whitewood Creek flows northeast from the figure 6 west edge (center south) to flow east along the figure 6 north edge before turning northeast again. Bear Butte Creek flows north and northeast in the figure 6 southeast corner. Boulder Creek flows east from the Mountain Meadow east end (figure 6 center) before turning southeast to join northeast-oriented Bear Butte Creek as a barbed tributary (southeast quadrant). Peedee Gulch flows northeast in the figure 6 southwest quadrant to join Boulder Creek east of Mountain Meadow. Two Bit Creek flows northeast in the figure 6 south center to join Boulder Creek where it begins to turn southeast. Spruce Gulch flows north-northwest in the figure 6 southeast corner to join northeast-oriented Whitewood Creek. Lost Gulch flows east-northeast to join north-oriented Bear Butte Creek in the figure 6 southeast corner. Northwest-oriented Sandy Creek is located in the figure 6 north center and two northeast-oriented tributaries are linked by high level through valleys to the Meadow Mountain-Boulder Creek through valley. The Mountain Meadow-Boulder Creek through valley was eroded primarily by east flowing flood water moving from what is now the Whitewood Creek drainage basin to what was then the newly eroded Bear Butte Creek valley. Flood waters moving east along the through valley used multiple routes to enter the Boulder Park area, with one route being the present day Boulder Creek-Bear Butte Creek valley route and another route being the through valley linking the Boulder Creek valley with Boulder Park utilized now by the highway. Evidence of these multiple flow routes is further evidence supporting the interpretation that an ever-changing southeast-oriented anastomosing complex of flood eroded channels was being captured by headward erosion of an ever-changing northeast-oriented complex of deeper valleys as elevations of the Black Hills domal uplift area were being raised relative to the surrounding plains region. Evidence of the through valleys (southeast of Whitewood Peak) linking northeast-oriented Sandy Creek tributary valleys with the east-oriented Mountain Meadow-Boulder Creek through valley explains how the northwest-oriented Sandy Creek valley was eroded. Headward erosion of the deep Whitewood Creek valley beheaded southeast-oriented flood flow on the Sandy Creek valley alignment and caused a reversal of flood flow. The reversed flood flow captured yet to be beheaded east-oriented flood flow on what was then a higher level Mountain Meadow-Boulder Creek flood flow route and the captured flood flow eroded the two northeast-oriented Sandy Creek tributary valleys (and also supplied the water needed to erode the northwest-oriented Sandy Creek valley). Subsequently the Mountain Meadow-Boulder Creek through valley was eroded much deeper to the level it is today before deep Whitewwood Creek headward erosion beheaded the east-oriented flood flow.

Whitewood Creek-Bear Butte Creek drainage divide area south of Deadwood, South Dakota

Figure 7: Whitewood Creek-Bear Butte Creek drainage divide area south of Deadwood, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the south end of the Whitewood Creek-Bear Butte drainage divide area and is located south of the figure 4 map area and includes overlap areas with figure 4. Whitewood Creek originates south of Deer Mountain near the figure 7 west center edge and flows south before making a U-turn to flow north-northeast to Englewood, Kirk, Pluma and Deadwood and the figure 7 north edge. Bear Butte Creek originates east of the Woodville Hills (just east of Englewood) as an east oriented stream and north of Brownsville (figure 7 center) turns northeast to flow toward the figure 7 northeast corner and to the figure 7 north edge. Note how many Bear Butte Creek tributaries are east oriented or southeast oriented and several Whitewood Creek tributaries are northwest oriented. This orientation of Bear Butte Creek and Whitewood Creek tributaries is evidence the deep Bear Butte Creek valley eroded headward into what is now the Black Hills domal uplift area to capture multiple east and southeast oriented flood flow channels, such as might be found in a southeast-oriented anastomosing channel complex. Further the tributaries provide evidence the deep Whitewood Creek valley subsequently eroded headward into what is now the Black Hills domal uplift area to behead the southeast-oriented flood channels, which were moving flood water to the newly eroded northeast-oriented Bear Butte valley. South of the Bear Butte Creek headwaters is east oriented Elk Creek, which flows through Brownsville and Roubaix before turning northeast to flow in a deep canyon to the figure 7 east edge. East of figure 7 Elk Creek turns to flow southeast and is discussed Belle Fourche River-Elk Creek drainage divide area essay. South of Elk Creek is southeast-oriented Hay Creek flowing to the east and southeast-oriented Boxelder Creek, which is discussed in Elk Creek-Boxelder Creek drainage divide area essay. South of the Whitewood Creek headwaters near Dumont (figure 7 southwest corner) are headwaters of southeast-oriented South Fork Rapid Creek. Through valleys linking Whitewood Creek, Rapid Creek, and Spearfish Creek were illustrated and discussed in the Spearfish Creek-Whitewood Creek drainage divide essay. Detailed maps below illustrate a through valley linking Whitewood Creek and Bear Butte Creek located southwest of Strawberry Ridge (figure 7 north center), through valleys linking the Whitewood Creek valley and Bear Butte and Elk Creek valleys in the Woodville Hills area, and the through valley linking the Elk Creek and Bear Butte Creek valleys (north of Brownsville).

Whitewood Creek-Bear Butte Creek drainage divide area at Strawberry Creek

Figure 8: Whitewood Creek-Bear Butte Creek drainage divide area at Strawberry Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 provides a detailed map of the through valley linking the northeast-oriented Whitewood Creek valley with the northeast-oriented Bear Butte Creek valley at Strawberry Creek (see figure 7 for location). Northeast-oriented Whitewood Creek is located in the figure 8 northwest corner. Northeast-oriented Bear Butte Creek flows from the figure 8 south edge (southeast quadrant) to the figure 8 east edge (northeast quadrant). Strawberry Creek flows northwest to Whitewood Creek in the figure 8 northwest corner. An unnamed southeast-oriented stream is linked by the through valley with Strawberry Creek headwaters and flows to northeast-oriented Bear Butte Creek. The northwest-southeast oriented highway defines the through valley today. Elevation where the highway crosses the Whitewood Creek-Bear Butte Creek drainage divide is 5732 feet, which is 150-160 feet lower than the crest of the hills on either side of the highway divide crossing. In other words, a northwest-southeast oriented valley at least 150 feet deep was eroded by southeast-oriented flood flow moving to the newly eroded northeast-oriented Bear Butte Creek valley before headward erosion of the deep Whitewood Creek beheaded the flood flow route and caused a reversal of flood flow. That flood flow reversal captured yet to be beheaded flood flow from flow routes further to the southwest and that captured flood water eroded what are today shallow high level valleys or notches in the ridge separating northwest-oriented Grizzly Gulch from northwest-oriented Strawberry Creek. That captured flood water eroded the deep northwest-oriented Strawberry Creek valley before Whitewood Creek valley headward erosion beheaded and reversed flood flow on the Grizzly Gulch alignment. The process probably was much more complicated than I have described because multiple ever-changing southeast-oriented flood flow channels were involved and flood flow routes to the deeper northeast-oriented valleys were also constantly changing.

Whitewood Creek-Bear Butte Creek drainage divide area at Woodville Hills

Figure 9: Whitewood Creek-Bear Butte Creek drainage divide area at Woodville Hills. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates a region southwest of the figure 8 map area and includes a small overlap area with figure 8. Whitewood Creek flows north-northeast from the figure 9 west edge to the figure 9 north edge (northwest quadrant). Bear Butte Creek originates in the figure 9 south center and flows east to the figure 9 east edge.  Elk Creek flows northeast from the figure 9 south center edge and then turns to flow east to the figure 9 east edge (southeast quadrant). A northwest-southeast oriented valley at Woodville links east oriented Bear Butte Creek headwaters with a northwest-oriented Whitewood Creek tributary valley. Other  through valleys link the Bear Butte Creek headwaters with an east oriented tributary flowing to the east oriented Elk Creek valley. The east-oriented Bear Butte Creek and Elk Creek valleys were probably components of an east- and/or southeast-oriented anastomosing channel complex that was captured by headward erosion of the deep northeast-oriented Bear Butte Creek valley and then eroded deeper to west into the Woodville area. About the time the deeper valleys reached the Woodville area headward erosion of the deep Whitewood Creek valley also reached the Woodville area and beheaded southeast-oriented flood flow on the through valley northeast of he Woodville Hills. Reversed flow on that valley eroded the northwest-oriented Whitewood Creek valley with help from captured flood waters from yet to be beheaded flood flow routes further to the south and southwest. The northeast-oriented Elk Creek valley probably was initiated by movement of such captured flood waters, but in time the east-oriented Elk Creek valley captured all the flow. The through valleys at Woodville are almost 400 feet lower than highest points in the Woodville Hills, suggesting as much as 400 feet of flood water erosion occurred in the Woodville area (and probably much in the deeper Bear Butte Creek and Elk Creek valleys further to the east in figure 9). In feet the Woodville valleys are almost 2400 feet higher today than the elevation of the Bear Creek valley where it joins the southeast-oriented Belle Fourche River valley at Volunteer, South Dakota. Hills in the figure 9 southwest corner provide even higher markers than the Woodville Hills to record the amount of flood erosion that occurred in this figure 9 map area, although other essays document even greater depths of flood erosion in other Black Hills domal uplifted drainage divide areas.

Bear Butte Creek-Elk Creek drainage divide area north of Roubaix, South Dakota

Figure 10: Bear Butte Creek-Elk Creek drainage divide area north of Roubaix, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 is a reduced map of the areas east of the figures 8 and 9 map areas and includes overlap areas with figures 8 and 9. Elk Creek flows east and northeast from the figure 10 southwest corner west edge to Brownsville and then east to Roubaix before turning northeast to flow through a deep canyon to the figure 10 east center edge. East-oriented Bear Butte Creek flows east from the figure 10 west edge to the north of Elk Creek and when it is north of Brownsville it turns northeast to flow to the figure 10 north edge (center east). The through valley at Strawberry Creek is located just southwest of Strawberry Ridge in the figure 10 northwest quadrant. Of special interest in figure 10 are through valleys linking the Elk Creek valley with the Bear Butte Creek valley just north of Brownsville. A close look at the map reveals several through valleys, with the highway using one of the through valleys. At one time flood water from the Elk Creek drainage basin upstream from the Brownsville area split in the Brownsville area with some flood flow going northeast to the northeast-oriented Bear Butte Creek valley and some flood flow continuing east to the northeast-oriented (and east of figure 10 southeast-oriented) Elk Creek valley. Probably headward erosion of the deep Elk Creek valley through the Elk Creek canyon to the east of Roubaix enabled the east-oriented Elk Creek valley to capture all the flood flow at Brownsville, beheading north-oriented flood flow to the Bear Butte Creek valley. This type of ever-changing flood flow pattern is typical of anastomosing channel complexes and probably occurred many times within the figure 10 map area prior to present day drainage networks being finalized.

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.

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