Missouri River-Hound Creek drainage divide area landform origins Lewis and Clark and Cascade Counties, Montana, USA

· Montana, MT Missouri River, Smith River
Authors

Abstract:

Topographic map interpretation methods are used to determine landform origins in the Missouri River-Hound Creek drainage divide area in Lewis and Clark and Cascade Counties, Montana. The study region is today a region of high mountains and deep valleys located between the north-northwest and north-northeast oriented Missouri River and east and north-oriented Hound Creek. Hound Creek is east of the Missouri River and today flows to the north-northwest oriented Smith River, which in turn flows to the Missouri River. Drainage divides throughout the study region are crossed by multiple through valleys (or saddles) notched into high and often narrow mountain ridges. These through valleys are interpreted to have been eroded as diverging and converging flood flow channels, which were eroded into an erosion surface equivalent in elevation to the highest study region elevations today. Flood waters were derived from a rapidly melting thick North American ice sheet and were flowing in south and southeast directions from Canada across Montana. Headward erosion of the deep Hound Creek valley and its tributary valleys first captured the south and southeast-oriented flood flow. Next headward erosion of the deep north-northeast oriented Missouri River valley beheaded the south and southeast-oriented flood flow channels. Flood waters on north and northwest ends of the beheaded flood flow channels reversed flow direction to erode deep north- and northwest-oriented tributary valleys. The north-northwest oriented Missouri River valley segment was eroded by such a reversal of flood flow and (outside of the study region) was successful in capturing significant flood flow from south and west of the actively eroding Missouri River valley head.

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-Hound Creek drainage divide area landform origins in Lewis and Clark and Cascade Counties, Montana, 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 providing 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-Hound Creek drainage divide area landform evidence in Lewis and Clark and Cascade Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see essay listed at header). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Missouri River-Hound Creek drainage divide area location map

Figure 1: Missouri River-Hound 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 illustrates a large region in central Montana and provides a location map for the Missouri River-Hound Creek drainage divide area in Lewis and Clark and Cascade Counties, Montana. The green shaded area near the figure 1 northwest corner is the south tip of Glacier National Park. The east-west continental divide extends in a south-southeast direction from Marias Pass (on the Glacier Park edge) along and near the Lewis and Clark Range crest to the figure 1 south edge (west of Helena and east of Butte). Figure 1 areas east of the continental divide drain to the Missouri River. The Missouri River flows in a north and north-northwest direction (west of the Big Belt Mountains) from Three Forks (just west of figure 1 south center edge) to near Wolf Creek and then turns to flow in a north-northeast and northeast direction to Great Falls, Fort Benton, and Loma before turning to flow in a south-southeast and east direction to the figure 1 east edge (north half). The Smith River is a north-northwest oriented tributary originating east of the Big Belt Mountains and joining the Missouri River a short distance upstream from Great Falls. The unlabeled south-oriented stream south of the Smith River headwaters and flowing between the Big Belt Mountains and the Crazy Mountains to the figure 1 south edge (east of center) is the Shields River, which flows to the east-, southeast, and northeast-oriented Yellowstone River (not seen in figure 1) which joins the Missouri River east of the figure 1 map area. Note west and southwest-oriented Smith River tributaries south of the Little Belt Mountains. Just east of these Smith River tributary headwaters are headwaters of the east-southeast oriented Musselshell River, which east of the figure 1 map area turns to flow in a north direction to join the Missouri River. An unlabeled north-northeast Smith River tributary originating in the northern Big Belt Mountains and flowing roughly in a parallel direction with the Missouri River before joining the Smith River is Hound Creek. The Missouri River-Smith River drainage divide landform origins north of the Big Belt Mountains essay illustrates and describes the region immediately north of the study region for this essay. Other Smith River drainage basin essays can be found by selecting Smith River from this essay’s sidebar category list.
  • The figure 1 map area, both east and west of the continental divide, was deeply eroded by immense south and southeast-oriented floods as present day valleys eroded headward into and across the region. Flood waters were derived from a rapidly melting thick North American ice sheet located in a deep “hole.” The Montana and northern Wyoming Missouri River drainage basin is located along what was the deep “hole’s” southwest wall. The deep “hole’s” western rim was located where the western Alberta and eastern British Columbia Rocky Mountains are now. Huge ice-marginal melt water floods flowed in south and southeast directions from that western rim into and across Montana. At that time flood waters flowed on an erosion surface, which if it is now preserved, is preserved at the highest level Rocky Mountain elevations. When the ice sheet first formed the deep “hole” did not exist and the ice sheet stood high above the surrounding non glaciated regions. The deep “hole” was formed by a combination of deep glacial erosion (under the ice sheet) and of crustal warping caused by the ice sheet’s tremendous weight. Ice sheet related crustal warping was responsible of present day mountain ranges and high plateau areas, including mountain ranges in the figure 1 map area. Uplift of mountain ranges may have been helped by crustal unloading as the massive south and southeast-oriented floods removed bedrock material from the rising mountain masses. The east-west continental divide was carved as deep valleys eroded headward from both the east and the west to capture the immense south and southeast-oriented melt water floods. Further south the east-oriented valleys eroded headward from the Gulf of Mexico and/or from south and/or southeast-oriented valleys which had eroded headward from the Gulf of Mexico. However, in Montana and northern Wyoming the deep valleys eroded headward from giant south and southeast-oriented ice-walled canyons carved by large supra-glacial melt water rivers into the decaying ice sheet’s surface. These deep northeast and east-oriented valleys eroded headward in sequence (from the southeast to the northwest) to capture the immense south and southeast-oriented melt water floods and to divert the flood waters into deep “hole” space the ice sheet had once occupied. The Missouri River valley seen in figure 1 was one such valley which eroded headward from the deep “hole” across Montana to capture the south and southeast-oriented flood waters and to divert those flood waters to melt water rivers flowing in the evolving deep “hole” space that was opening up.
  • East of the Big Belt Mountains headward erosion of the deep Missouri River valley across Montana beheaded deep south and southeast-oriented flood flow channels which were eroding headward from what was then the newly eroded Yellowstone River valley, which had previously eroded headward from the deep “hole” to capture south and southeast-oriented flood flow. Some of these deep south and southeast-oriented flood flow channels were located between rising mountain ranges, although evidence of earlier south and southeast-oriented flood flow channels can also be found on the mountain range crests. The Missouri River valley, where it beheaded these south and southeast-oriented flood flow channels, was much deeper than the flood flow channels and flood waters on north ends of beheaded flood flow channels reversed flow direction to erode north and northwest-oriented Missouri River tributary valleys, several of which can be seen in figure 1. The Smith River seen in figure 1 is a good example of a river flowing in a valley eroded by a reversal of south-southeast oriented flood flow, which had been moving to the newly eroded Yellowstone River valley and also to the actively eroding Musselshell River valley. The emerging Big Belt, Little Belt, Crazy, and other regional mountain ranges gradually channeled the south and southeast-oriented flood flow along routes between what were their rising mountain masses (which were rising faster than the flood waters could erode them). The north-northeast oriented Missouri River valley, which eroded headward across this major south-southeast oriented flood flow channel, was significantly deeper than the flood flow channel. Flood waters on the north-northwest end of the beheaded flood flow channel reversed flow direction to erode the north-northwest oriented Smith River valley. Headward erosion of the deep Missouri River valley beheaded south- and southeast-oriented flood flow channels one channel at a time. As a result reversed flood flow in a newly beheaded and reversed flood flow channel could capture south- and southeast-oriented flood flow from south and west of the actively eroding Missouri River valley head. This captured flood flow often moved in east and northeast directions to the newly reversed flood flow channel and eroded east and north-northeast oriented tributary valleys along routes such as the Hound Creek route in figure 1. The north-northwest oriented Missouri River valley upstream from Holter Lake was also eroded by a reversal of flood flow on the north-northwest end of a south-southeast oriented flood flow channel beheaded by Missouri River valley headward erosion.

Detailed location map for Missouri River-Hound Creek drainage divide area

Figure 2: Detailed location map for Missouri River-Hound Creek drainage divide area.United States Geological Survey map digitally presented using National Geographic Society TOPO software.  

  • Focusing now on the Missouri River-Hound Creek drainage divide area in Lewis and Clark and Cascade Counties figure 2 provides a more detailed location map. Green shaded area are National Forest lands and are generally located in mountainous regions. The Lewis and Clark-Cascade County line is shown with Cascade County located east of Lewis and Clark County. Meagher County is the unlabeled county in the figure 2 southeast quadrant. The Missouri River flows in a north-northwest direction from the figure 2 south edge (along west edge of green shaded area straddling figure 2 south center edge) to Holter Dam and then turns to flow in a north-northeast direction to the figure 2 north edge (east half). The Smith River flows in a north-northwest, north and north-northwest direction from the figure 2 south edge (near southeast corner) to join the Missouri River just north of the figure 2 map area. Hound Creek originates south of Adel in the figure 2 south center area and flows in a northeast and north direction to join the Smith River south of Ming Coulee Ridge. The West Fork Hound Creek flow in an east direction north of Adel. Missouri River tributaries in the Missouri River-Hound Creek drainage divide area are unlabeled, but are generally oriented in northwest directions. The figure 2 map does not show topography, but as will be seen in the topographic maps below the drainage divide area south of the 4th Standard Parallel is a high mountain region with the Missouri River, Hound Creek, and their tributaries generally flowing in deep valleys. North of the 4th Standard Parallel the Missouri River-Hound Creek drainage divide area, while definitely containing hills and valleys, is much lower in elevation and is illustrated and discussed in the Missouri River-Smith River drainage divide area landform origins north of the Big Belt Mountains essay. My interpretation of the two quite different Missouri River-Hound Creek drainage divide area landform origins, north and south of the 4th Standard Parallel, is that they eroded by massive southeast-oriented floods, captured first by headward erosion of the deep northeast and north-oriented Hound Creek valley and subsequently captured by headward erosion of the deep north-northeast oriented Missouri River valley. The northwest-oriented Missouri River tributary valleys are interpreted to have been eroded by reversals of flood flow on northwest ends of beheaded flood flow channels. To be correct this interpretation requires either very deep erosion of the region north of the 4th Standard Parallel or uplift of the mountains (south of the 4th Standard Parallel) to have been occurring as flood waters flowed across the region. Neither of these interpretations will be regarded as likely by geologists thinking in terms of uniformitarianism, but after studying the topographic maps evidence such skeptical geologists may be forced to consider the possibility.

Sheep Creek-West Fork Hound Creek drainage divide area

Figure 3: Sheep Creek-West Fork Hound Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 3 illustrates the Sheep Creek-West Fork Hound Creek drainage divide area at the north end of the mountainous region along the Missouri River-Hound Creek drainage divide area. Note how the mountains end near the figure 3 north edge. As previously noted the Missouri River-Hound Creek drainage divide area north of figure 3 is illustrated and described in the Missouri River-Smith River drainage divide area landform origins north of the Big Belt Mountain, Montana essay. The Missouri River flows in a north-northeast direction in the figure 3 northwest corner. Sheep Creek is the northwest oriented tributary joining the Missouri River near Hardy in the figure 3 northwest corner and has a northwest-oriented North Fork north of Black Mountain and a west and north-northwest oriented South Fork south of Black Mountain. The West Fork Hound Creek flows in an east direction north of the Pinnacles in the figure 3 southeast quadrant and joins north-oriented Hound Creek east of the figure 3 map area. Squaw Creek is the major southeast-oriented tributary joining the West Fork Hound Creek a short distance downstream from Squaw Hollow. What is particularly intriguing about the figure 3 drainage pattern is the Missouri River tributaries are oriented in northwest directions or have significant northwest-oriented segments. At the same time the West Fork Hound Creek headwaters and at least one major tributary are oriented in southeast directions. Further study of the Missouri River-Hound Creek drainage divide reveals the northwest (and west) oriented Missouri River tributary valleys are linked by shallow through valleys (or saddles) notched into the high drainage divide ridges. For example, west of Black Mountain a northwest-southeast oriented through valley links the northwest-oriented North Fork Sheep Creek valley with the southeast-oriented Squaw Creek valley. The figure 3 map contour interval is 50 meters and the through valley floor elevation at the drainage divide is between 1800 and 1850 meters. While this is more than 250 meters higher than floors of the deep northwest- and southeast-oriented valleys on either side it is also at least 200 meters lower than high points on the drainage divide ridge in either direction. This through valley was eroded by southeast-oriented flood flow moving to what was then an actively eroding Squaw Creek valley at a time when the deep north-northeast oriented Missouri River valley did not exist. Headward erosion of the deep north-northeast oriented Missouri River valley beheaded the southeast-oriented flood flow and flood waters on the northwest end of the beheaded flood flow channel reversed flow direction to erode the northwest-oriented North Fork Sheep and Sheep Creek valleys. While this description greatly over simplifies what happened it does describe the process that occurred over and over again as flood flow channels eroded deep valley headward into the mountain mass and then as headward erosion of much deeper valleys beheaded and reversed those flood channels to erode deep valleys oriented in the opposite direction.

Detailed map of North Fork Sheep Creek-West Fork Hound Creek drainage divide area

Figure 4: Detailed map of North Fork Sheep Creek-West Fork Hound Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 4 uses a detailed topographic map to better illustrate the North Fork Sheep Creek-Squaw Creek drainage divide area seen in less detail in figure 3. The North Fork Sheep Creek originates in section 25 and flows in a north-northeast direction to the figure 4 north edge (near northwest corner). Also originating in section 25 (south of the North Fork Sheep Creek headwaters) is west-oriented South Fork Sheep Creek, which flows to the figure 4 west edge (south half) and west of the figure 4 map area turns to flow in a north-northwest direction. Note how in section 25 there is a through valley linking the north-northwest oriented North Fork Sheep Creek valley with the west-oriented South Fork Sheep Creek valley. The figure 4 map contour interval is 40 feet and the through valley floor elevation at the drainage divide is between 5680 and 5720 feet. Note also that the North Fork Sheep Creek valley floor at the north edge of section 25 has an elevation of 5000 while the South Fork Sheep Creek valley floor elevation at the section 25 west edge has an elevation of between 5120 and 5160 feet, meaning the South Fork valley has not been eroded as deep in section 25 as the North Fork valley. Elevations in section 25 directly northwest of the through valley rise to 5986 feet while the ridge across the section 25 southeast corner rises to more than 6200 foot in places. The through valley (or saddle) notched into the drainage divide between north-northeast oriented North Fork Sheep Creek and southeast-oriented Squaw Creek (near corner of sections 19, 24, 25, and 30) has an elevation of between 5960 and 6000 feet, with an elevation of 6512 feet being located in section 19 to the north and east and an elevation of 6662 feet being located in the section 36 northeast corner to the south, meaning the through valley when eroded was at least 500 feet deep. The high North Fork Sheep Creek-Squaw Creek through valley was eroded by southeast-oriented flood flow moving to what then the actively eroding southeast-oriented Squaw Creek valley. Headward erosion of the deep Missouri River valley beheaded and reversed the flood flow channel to erode the north-northwest oriented North Fork Sheep Creek valley.
  • But, today the North Fork Sheep Creek valley is as deep or deeper than the Squaw Creek valley. The question can be validly asked where did the water to erode the deep north-northwest oriented North Fork Sheep Creek valley come from? The answer is Missouri River valley headward erosion beheaded flood flow channels one channel at a time, which means reversed flood flow on a newly beheaded flood flow channel could capture flood waters from south and west of the actively eroding Missouri River valley head. Such captured flood flow moved in east and northeast directions to the newly reversed flood flow route and what is today the west-oriented South Fork Sheep Creek valley was initiated by such captured flood water moving in an east and northeast-oriented flood flow channel to the newly and reversed flood flow on the North Fork Sheep Creek flood flow channel alignment. Flood flow in this east-oriented flood flow channel was subsequently beheaded and reversed to erode the west-oriented South Fork Sheep Creek valley. Again flood flow movements were more complex than described in this simplified version. What is important to remember is each of the through valleys (or saddles) notched into the high ridges seen in figure 4 was at one time a flood flow channel in what was a giant anastomosing channel complex crossing the entire region. The flood flow channels had been eroded into an erosion surface which extended across the entire region (there were no deep valleys at first). Headward erosion of the deep east-oriented West Fork Hound Creek valley and its southeast-oriented Squaw Creek valley first captured the south and southeast-oriented flood water. Next headward erosion of the deep north-northeast oriented Missouri River beheaded and reversed the flood flow channels in sequence from the northeast to the southwest. Because the flood flow channels were anastomosing reversed flood flow could capture yet to be reversed flood flow from adjacent flood flow channels. At the same time crustal warping was probably raising the entire figure 4 mountain mass, which further complicated flood flow movements and which helped in the erosion of the deep valleys.

Detailed map of South Fork Sheep Creek-West Fork Hound Creek drainage divide area

Figure 5: Detailed map of South Fork Sheep Creek-West Fork Hound Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 5 provides a detailed topographic map of the South Fork Sheep Creek-West Fork Hound Creek drainage divide area located south of the figure 4 map area and includes overlap areas with figure 4. West Fork Sheep Creek flows in a west direction near the north edge of the figure 5 northwest quadrant. The east-oriented stream in the figure 5 northeast corner is a tributary to southeast oriented Squaw Creek (which is located north and east of the figure 5 map area). The east-oriented stream in the figure 5 southeast quadrant is the West Fork Hound Creek and the Pinnacles (seen in figure 3) is located south of the figure 5 southeast quadrant. Note how the West Fork Hound Creek has multiple southeast and south-southeast oriented tributaries from the north and how the South Fork Sheep Creek has multiple north-northwest oriented tributaries from the south. Study of the South Fork Sheep Creek-West-Fork Hound Creek drainage divide reveals through valleys (or saddles) notched into the high ridge which link the north-northwest oriented South Fork Sheep Creek tributary valleys with the southeast and south-southeast oriented West Fork Hound Creek tributary valleys. Elevations of the floors of these through valleys are quite high (even higher than the North Fork Sheep Creek-Squaw Creek drainage divide elevations) and are recording an earlier higher level set of south-southeast oriented flood flow channels which once crossed the region. For example the deepest through valley in section 36 has an elevation at the drainage divide of between 6280 and 6320 feet (the figure 5 map contour interval is again 40 feet). While based on today’s topography the concept of diverging and converging southeast-oriented flood flow channels crossing the figure 5 map area seems intuitively impossible, however that is what the tributary valley orientations and the through valleys across the drainage divide are suggesting was the case before headward erosion of the present day deep valleys (especially north and west of the drainage divide). The west-oriented South Fork Sheep Creek valley was apparently initiated as an east-oriented flood flow channel at an elevation high enough for flood waters to flow into the West Fork Hound Creek valley prior to being captured by reversed flood flow on the North Fork Sheep Creek alignment as described in figure 4. Again there are many more complexities, but the evidence again suggests flood waters flowed on an erosion surface equivalent in elevation to the highest figure 5 elevations today prior to headward erosion of the present day deep valleys. Probably crustal warping was raising the figure 5 map region as the flood waters flowed across it and greatly aided the deep valley headward erosion process.

Stickney Creek-Hound Creek drainage divide area

Figure 6: Stickney Creek-Hound Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 6 illustrates the Stickney Creek-Hound Creek drainage divide area south and slightly west of figure 3 and includes overlap areas with figure 3. Squaw Creek flows in a southeast direction across the figure 6 northeast corner and joins east-oriented West Fork Hound Creek just east of the figure 6 east edge (north half). Hound Creek is formed at the confluence of north-northeast oriented Tyrell Creek and south-oriented Pole Creek at Hound Creek Reservoir (in figure 6 southeast quadrant) and flows in an east-southeast direction before being joined by east-northeast oriented Middle Creek and north-oriented (Elk) Creek near the figure 6 southeast corner and then flows in an east-northeast direction to the figure 6 east edge (south half). East and north of the figure 6 map area Hound Creek turns to flow in a north-northeast direction to reach the north-northwest oriented Smith River. Spring Creek is the south-southeast oriented Hound Creek tributary east of Pole Creek and Encampment Creek is the east-southeast oriented tributary east of Spring Creek flowing from the Pinnacles near the small town of Adel to join Hound Creek east of the figure 6 map area. Mount Rowe is the labeled mountain peak near the figure 6 northwest corner. The northwest, west, and southwest-oriented stream north of Mount Rowe is the North Fork Stickney Creek while the northwest-oriented stream making a jog to the south around the south side of Mount Rowe is the South Fork Stickney Creek. West of the figure 6 northwest corner the North and South Forks join to form north-northwest oriented Stickney Creek, which then flows to the north-northeast oriented Missouri River. The northwest-oriented stream south of northwest-oriented South Fork Stickney Creek is Wegner Creek, which near the figure 6 west edge turns to flow in a west-northwest direction to the Missouri River (west of figure 6). Note how northwest-oriented South Fork Stickney Creek originates in the region northwest of Hound Creek Reservoir and is linked by a through valley with the Hound Creek valley. The figure 6 map contour interval is 50 meters and the through valley floor elevation at the drainage divide is between 1700 and 1750 meters. Also note how the northwest-oriented South Fork Stickney Creek valley is deeper than the Hound Creek valley. The through valley was probably initially eroded by southeast-oriented flood flow to what was then the actively eroding Hound Creek valley and to a diverging south-oriented flood flow channel on the present day north-oriented Tyrell Creek alignment. Headward erosion of the deep north-northeast oriented Missouri River valley then beheaded and reversed the southeast-oriented flood flow which eroded the northwest-oriented South Fork Stickney Creek-Stickney Creek valley. Apparently large volumes of flood water from south and west of the actively eroding Missouri River valley head flowed into the Hound Creek Reservoir area by reversing flow in what had been south-oriented flood flow channels (e.g. Tyrell Creek alignment) and then for a time at least some water flowed in a northwest direction to the actively eroding Missouri River valley head. Before Missouri River valley headward erosion cut off the flood flow headward erosion of the deep Hound Creek valley captured the north- and northwest-oriented flood flow and diverted the flood water to the Smith River creating the present day divide.

Detailed map South Fork Stickney Creek-East Fork Hound Creek drainage divide area

Figure 7: Detailed map South Fork Stickney Creek-East Fork Hound 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 South Fork Stickney Creek-East Fork Hound Creek drainage divide area seen in less detail in figure 6 above. The South Fork Stickney Creek flows in a northwest direction to the figure 7 northwest corner. Wegner Creek is the north-northwest oriented stream seen near the west edge of the figure 7 southwest quadrant. Hound Creek Reservoir is located in section 35 and the East Fork Hound Creek (Hound Creek on figure 6) flows in an east-southeast direction from Hound Creek Reservoir to the figure 7 east center edge. Tyrell Creek is the north-northeast and northeast-oriented stream flowing from the figure 7 south center edge to Hound Creek Reservoir. Pole Creek flows in a south direction from the figure 7 north edge (east of center) to the west end of Hound Creek Reservoir and Spring Creek flows in a south-southeast direction from the figure 7 north edge (east of Pole Creek) to join the East Fork Hound Creek in section 31 (near figure 7 east center edge). Note the through valleys in section 22 southwest corner and section 27 northeast quadrant and section 22 southeast quadrant linking the east-southeast oriented East Hound Creek valley with the northwest-oriented South Fork Stickney Creek valley. The figure 7 map contour interval is 40 feet and both through valleys have elevations of between 5440 and 5480 feet at the drainage divide. Elevations north of the figure 7 map area rise to more than 6200 feet while elevations in section 33 rise to more than 6000 feet suggesting the through valleys are least 500 feet deep. The Hound Creek Reservoir elevation is between 5080 and 5120 feet while the South Fork Stickney Creek valley elevation in the northwest corner of section 28 is between 4800 and 4840 feet suggesting the through valley floor elevations are at least 400 feet higher than valleys on either side and that the South Fork Stickney Creek valley becomes deeper faster than the East Fork Hound Creek becomes deeper. The through valleys are water eroded features and were probably initially eroded by southeast-oriented flood flow although the deeper South Fork Stickney Creek valley suggests after headward erosion of the deep north-northeast oriented Missouri River valley beheaded and reversed the flood flow the reversed flood flow captured flood waters from west and south of the actively eroding Missouri River valley head. The captured flood flow moved north on the Tyrell Creek alignment with some water going in a northwest direction to the actively eroding South Fork Stickney Creek valley while most of the flood water flowed to the actively eroding Hound Creek valley, which eventually captured all of the north-oriented flood flow (from south and west of the Missouri River valley head) before headward erosion of the deep Missouri River valley ended all flood flow to the figure 7 map area.

Detailed map of Wegner Creek-Tyrell Creek drainage divide area

Figure 8: Detailed map of Wegner Creek-Tyrell Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 8 is a detailed topographic map of the Wegner Creek-Tyrell Creek drainage divide area south and west of the figure 7 map area and includes overlap areas with figure 7. Tyrell Creek flows in a north-northeast direction from the figure 8 south edge (in section 9) to the figure 8 north edge (near northeast corner). Wegner Creek originates in section 8 (and flows in a north-northwest and northwest direction to the figure 8 north edge (west half). Note how in the southeast corner of section 8 and the southwest corner of section 9 there is a through valley linking a northwest-oriented Wegner Creek headwaters valley with an east-oriented Tyrell Creek tributary valley. The figure 8 map contour interval is 40 feet and the through valley floor elevation at the drainage divide is between 5920 and 5960 feet. Other slightly higher through valleys can be found in the north half of section 17 and then further north along the Wegner Creek-Tyrell Creek drainage divide all the way to the figure 8 north edge. Perhaps the most interesting through valley is located in section 17 near the figure 8 south edge and links the north-northwest oriented Wegner Creek valley with the a southeast oriented Tyrell Creek tributary valley. A high point on the drainage divide in section 17 is shown with an elevation of 6463 feet and elevations greater than 7800 feet can be found south of the Tyrell Creek headwaters. Proceeding in a north direction elevations greater than 7000 feet are found north of the northwest-oriented South Fork Stickney Creek headwaters. While it can be debated which adjacent drainage divide elevations should be used to determine the through valleys depth the through valleys without question are several hundred feet deep and may be channels eroded into the floor of what was once a much broader and deeper southeast-oriented valley eroded between the previously mentioned high points to the north and south. The through valleys are water eroded features and were initially eroded by southeast-oriented flood flow moving across the figure 8 map area. Headward erosion of the deep north-northeast oriented Missouri River valley beheaded the southeast-oriented flood flow and flood waters on the north and northwest ends of the beheaded flood flow channels reversed flow direction to erode the northwest oriented Stickney Creek and tributary valleys (north of figure 8). Headward erosion of the newly reversed and much deeper Stickney Creek valley captured flood flow from south and west and the actively eroding Missouri River valley which was moving on the Wegner Creek alignment and for a time this captured flood water flowed in north and northeast directions in the Tyrell Creek valley to the actively eroding and much deeper north-northwest oriented Stickney Creek valley. Headward erosion of a deeper Hound Creek-Tyrell Creek valley then captured the northeast-oriented flood flow that had been moving to the Stickney Creek valley. Headward erosion of the deep Missouri River valley then beheaded and reversed the Wegner Creek flood flow channel and the process was repeated again further to the south.

Missouri River-Hound Creek drainage divide area

Figure 9: Missouri River-Hound Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 9 illustrates the Missouri River-Hound Creek drainage divide area south and west of the figure 6 map area and includes overlap areas with figure 6. The meandering and north-northwest oriented Missouri River valley is located near the figure 9 west edge and is flooded by Holter Lake. Missouri River tributaries from the east (from north to south) include southwest-oriented Log Gulch and Cottonwood Creek and west-northwest, west-southwest, and southwest oriented Elkhorn Creek and its west-oriented tributary Willow Creek. Cottonwood Creek has several southeast-oriented tributaries from the northwest and northwest-oriented tributaries from the southeast suggesting the southwest-oriented Cottonwood Creek valley eroded headward across southeast-oriented flood flow channels and reversed flood flow on northwest ends of the beheaded flood flow channels. Hound Creek Reservoir can be seen near the figure 9 northeast corner. Tyrell Creek flows in a north-northeast and northeast direction from the figure 9 east center region to Hound Creek Reservoir. Note how Tyrell Creek has several northwest-oriented tributaries, which flow in valleys eroded by flood waters on northwest ends of beheaded southeast-oriented flood flow channels. Wegner Creek originates just east of the county line and north of the Tyrell Creek headwaters and flows in a north-northwest direction to the figure 9 north center edge. The northwest-oriented headwaters of the South Fork Stickney Creek can be seen east of Wegner Creek and the county line near the figure 9 north edge. Focusing on through valleys one through valley of interest links the north-oriented Cottonwood Creek headwaters with a west- and southwest-oriented Elkhorn Creek tributary valley. The through valley is just east of the county line and is underneath the words “CASCADE CO”. Just to the west on the Lewis and Clark County side of the county line is a northwest-southeast through valley linking a northwest-oriented Cottonwood Creek tributary valley with a south oriented Elkhorn Creek tributary valley. Continuing in a west direction along the Cottonwood Creek-Elkhorn Creek drainage divide several more through valleys can be seen. At least some of these through valleys are probably eroded between dipping strata and are related to the underlying geologic structures, however each of the through valleys is a water eroded feature and provides evidence of south- and southeast-oriented flood flow that once flowed across the region. The southwest orientations of the Cottonwood Creek and Elkhorn Creek valley segments near the Missouri River suggests these deep valleys initially eroded headward from a deep south-southeast oriented flood flow channel. Headward erosion of the deep north-northeast-oriented Missouri River valley north of the figure 9 map area beheaded that deep south-oriented flood flow channel and flood waters on the north-northwest end of the beheaded flood flow reversed flow direction to erode the north-northwest oriented Missouri River valley which then captured the southwest-oriented tributary valleys.

Detailed map of Cottonwood Creek-Tyrell Creek drainage divide area

Figure 10: Detailed map of Cottonwood Creek-Tyrell Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software. 

  • Figure 10 provides a detailed topographic map of the Cottonwood Creek-Tyrell Creek drainage divide area seen in less detail in figure 9 and south and west of the figure 8 map area and includes overlap areas with figure 8. Tyrell Creek flows in a north and north-northeast direction in the figure 10 east half. Wegner Creek originates in section 8 and flows in a north-northwest direction to the figure 10 north edge (west of center). Cottonwood Creek flows near the county line between section 7 and sections 12 and 13 and then turns to flow in a west direction across section 12 to the figure 10 west edge (north half). The west and south-southwest oriented stream in sections 17 and 18 in the figure 10 south center area is a tributary to Elkhorn Creek. Note how in the section 18 southwest quadrant the north-oriented Cottonwood Creek valley is linked by a through valley with west and south-southwest oriented Elkhorn Creek tributary valley. In the north half of section 17 the north-northwest oriented Wegner Creek valley is linked by through valleys with a southeast-oriented tributary to north-oriented Tyrell Creek. Near the corner of sections 16, 17, 20, and 21 another through valley links the west and south-southwest oriented Elkhorn Creek tributary valley with the north-oriented Tyrell Creek valley. Just north of the corner of sections 8, 9 16, and 17 is a still another through valley linking the north-northwest oriented Wegner Creek valley with the north-oriented Tyrell Creek valley. These are some of the many through valleys seen in the region linking the various present day drainage routes. The through valleys are all water eroded features and can best be explained in the context of flood flow channels, which were eroded initially into an erosion surface equivalent in elevation to the highest figure 10 elevations today. Initially the flood waters were flowing in south and southeast directions, although headward erosion of deep valleys into the region set up complex flood flow movements as flood waters moving in the diverging and converging flood flow channels were reversed by flood flow captures and/or when beheaded by much deeper valleys, such as the much deeper north-northeast-oriented Missouri River valley north of the figure 10 map area. Some these flood flow reversals were very successful in capturing large volumes of flood water from further to the west and south with the flood flow reversal that eroded the deep Missouri River valley seen in figure 10 being the most successful of all in capturing significant south-southeast oriented flood flow (south and west of figure 10) and then diverting that captured flood flow to move across the figure 10 map area.

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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