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.

• The purpose of this essay is to use topographic map interpretation methods to explore the Hound Creek-Smith River drainage divide area landform origins in Cascade and Meagher 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 by providing a link to the 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 because of its tremendous 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 Hound Creek-Smith River drainage divide area landform evidence in Cascade and Meagher 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.

Figure 1: Hound Creek-Smith River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software.

 

Figure 1 illustrates a large region in central Montana and provides a location map for the Hound Creek-Smith River drainage divide area in Cascade and Meagher 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 Glacier National Park along or near the Lewis and Clark Range crest to the figure 1 south edge (west half-between Butte and Helena). All drainage routes east of the continental divide flow to the Missouri River with water eventually reaching the Gulf of Mexico. The Missouri River flows in a north and north-northwest direction from Three Forks (near figure 1 south center edge) along the west side of the Big Belt Mountains to just north of Holter Lake and then turns to flow in a northeast direction to Great Falls, Fort Benton, and Loma. South of the town of Big Sandy (near figure 1 north edge-north and east of Loma) the Missouri River makes an abrupt turn to flow in a south-southeast and east direction to the figure 1 east edge (north half). The Smith River originates on the east side of the Big Belt Mountains and flows in a north-northwest direction between the Big Belt Mountains and the Little Belt Mountains to join the Missouri River near the town on Ulm (just upstream from Great Falls). South of the Smith River headwaters, between the Big Belt Mountains and the Crazy Mountains are headwaters of the south-southeast oriented 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. Between the Little Belt Mountains and the Crazy Mountains are headwaters of the east-oriented Musselshell River, which flows to the figure 1 east edge (south half) and which east of figure 1 turns to flow in a north direction to join the Missouri River. Smith River tributaries from the west are not labeled, but the northernmost tributary is Hound Creek and originates at the north end of the Big Belt Mountains and flows in a northeast direction to join the Smith River. Further south (just north of the words “Hauser Lake”) is Rock Creek, which flows in an east direction from the Big Belt Mountains to join the north-northwest oriented Smith River. The Hound Creek-Smith River drainage divide area investigated in this essay is located north of Rock Creek, east of Hound Creek and west of the Smith River. Essays illustrating and describing other Smith River drainage divide areas can be found by selecting Smith River from this essay’s sidebar category list.

• Drainage routes in the figure 1 map area, both east and west of the continental divide, were formed by headward erosion of deep valleys along and across massive south and southeast oriented floods which flowed across the entire figure 1 map area. Flood waters were derived from a rapidly melting thick North American ice sheet located in a deep “hole.” The Missouri River drainage basin in Montana and northern Wyoming is formed on the deeply eroded deep “hole” southwest wall. The Canadian Rockies in western Alberta and eastern British Columbia emerged as the deep “hole’s” western rim. Immense ice-marginal melt water floods flowed from that deep “hole” western rim in Canada in south and southeast directions into and across Montana and then further south. When the thick ice sheet first formed there was no deep “hole” and the deep “hole” was created by deep glacial erosion (under the ice sheet) and by crustal warping caused by the ice sheet’s tremendous weight. Crustal warping raised mountain ranges and high plateau areas including the figure 1 map area mountain ranges, the Rocky Mountains in general, and the Colorado Plateau. Prior to the uplift of these mountain ranges and high plateau areas flood waters could freely flow in a south and southeast direction from the ice sheet’s western rim to the Gulf of Mexico along routes corresponding with the east-west continental divide. The continental divide was formed as deep valleys eroded headward from the Gulf of Mexico in the east and the Pacific Ocean in the west to capture the immense south and southeast oriented flood flow with the rising Rocky Mountains helping in the process.

• Eventually a combination of mountain uplift and of ice sheet melting created a situation where the immense south and southeast oriented melt water floods in Montana and northern Wyoming were flowing on bedrock surfaces higher in elevations than the adjacent ice sheet surface, especially the elevation of floors of deep ice-walled canyons being carved into the decaying ice sheet surface. Of particular importance to the figure 1 map area was a giant southeast and south oriented ice-walled canyon in present day Saskatchewan, North Dakota, and South Dakota. In time this giant ice-walled canyon became an ice-walled and bedrock-floored canyon and detached the ice sheet’s southwest margin. Today the northeast and east facing Missouri Escarpment is what remains of that giant ice-walled and bedrock-floored canyon’s southwest and west wall. Deep northeast and east oriented valleys eroded headward from that giant ice-walled canyon in sequence (from the southeast to the northwest) to capture the immense south and southeast-oriented floods moving across Montana and northern Wyoming. The Missouri River valley seen in figure 1 was one of those deep valleys and beheaded south and southeast-oriented flood flow to what was then the newly eroded Yellowstone River valley, which had eroded headward in advance of the Missouri River valley. Flood waters on north and northwest ends of beheaded flood flow routes reversed flow direction to erode north and northwest-oriented Missouri River tributary valleys. The north-northwest oriented Smith River valley seen in figure 1 was eroded by such a reversal of flood flow as was the north-northwest oriented Missouri River valley segment seen in figure 1. Headward erosion of each deep east and northeast-oriented valley captured south and southeast-oriented flood flow to the newly eroded valley immediately to the south and east and beheaded flood flow routes so as to cause flood flow reversals and erosion of north- and northwest-oriented valleys.

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

 

Focusing now on this essay’s study region the figure 2 map provides a detailed location map for the Hound Creek-Smith River drainage divide area. County boundaries are shown and Meagher County is located in the figure 2 southeast region. Cascade County is north of Meagher County. Green shaded areas are National Forest lands, which are generally located in mountainous regions. The green shaded area straddling the figure 2 east edge is located in the Little Belt Mountain Range. The green shaded area straddling the figure 2 south edge is located in the Big Belt Mountain Range. The Missouri River flows in a northwest direction along the Big Belt Mountain Range southwest margin to Holter Dam (near figure 2 west edge) and then turns to flow in a north-northeast direction to the figure 2 north edge (west half). The Smith River flows in a north-northwest direction from the figure 2 south edge (east half) to the west margin of the Little Belt Mountains National Forest land area. After flowing in a north direction along the west margin of the green shaded area the Smith River turns to flow in a north-northwest direction to the figure 2 north center edge. Hound Creek originates just north of the Big Belt Mountains National Forest land area and flows in a northeast and north-northeast direction to join the Smith River near the figure 2 north center edge. Labeled Smith River tributaries south and east of Hound Creek include northeast-oriented Trout Creek and east-oriented Rock Creek. Hound Creek has two unlabeled north-oriented tributaries in the region just north of the National Forest lands. As stated in the figure 1 discussion the north-northwest oriented Smith River flows in a valley that was initiated as a south-southeast flood flow channel to what was then the actively eroding Yellowstone River valley. At that time the Little Belt Mountains and Big Belt Mountains were not high mountain ranges as seen today, but were rising as south and southeast-oriented flood waters flowed across them. Headward erosion of what was then a much deeper northeast-oriented Missouri River valley (north of figure 2) beheaded the south-southeast flood flow channel on the Smith River alignment and 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 (which was probably aided by crustal warping occurring at that time). Reversed flood flow on the deep north-northwest oriented Smith River alignment captured significant south and southeast-oriented flood flow from west and south of the actively eroding Missouri River valley head. That captured flood flow moved in east, northeast, and north-northeast directions and eroded deep Smith River tributary valleys. Headward erosion of the deep east-oriented Rock Creek valley captured south and southeast-oriented flood flow and diverted the water to the Smith River valley. Next headward erosion of the deep northeast-oriented Trout Creek valley captured southeast-oriented flood flow and diverted it to the Smith River valley. Finally headward erosion of the deep northeast and north-northeast oriented Hound Creek valley captured the south- and southeast-oriented flood flow and diverted it to the Smith River valley. Missouri River valley headward erosion then beheaded all south- and southeast-oriented flood flow routes to the newly eroded Hound Creek valley.

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

 

Figure 3 illustrates the Hound Creek-Trout Creek drainage divide area. The Smith River meanders in a north direction near the figure 3 east edge and turns to flow in a north-northwest direction near the figure 3 north edge. (Clark) Creek is a north-oriented Smith River tributary flowing to the figure 3 north edge (east half). West of Clark Creek is north-oriented Mullens Creek, which is a Clark Creek tributary and which flows to the figure 3 north edge (just east of center). Hound Creek flows in a north-northeast direction in the figure 3 west half and joins the north-northwest oriented Smith River north of the figure 3 map area. Spring Creek is a north-oriented Hound Creek tributary and joins Hound Creek just north of the figure 3 map area. Porcupine Creek is a west-northwest oriented Hound Creek tributary located north of Conway Ridge in the figure 3 southwest quadrant. Millegan is the small town located near the figure 3 south edge (east half). Trout Creek is the northeast-oriented Smith River tributary flowing through Millegan. Other than a few southeast-oriented Hound Creek tributaries the figure 3 map area is dominated by north-oriented drainage routes. These north-oriented drainage routes were formed during systematic reversals of south and southeast-oriented flood flow across the entire figure 3 map area which was beheaded from east to west by headward erosion of a very deep north-northeast oriented Missouri River valley north and west of the figure 3 map area. Prior to Missouri River valley headward erosion the south and southeast-oriented flood flow was eroding diverging and converging south-oriented flood flow channels into an erosion surface as high as the highest figure 3 elevations today. The deepest of these flood flow channels was apparently along the present day Smith River alignment and was moving flood waters to the newly eroded Yellowstone River valley south of the figure 3 map area and this essay’s study region. When beheaded by headward erosion of the much deeper Missouri River valley flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the present day north-oriented and deep Smith River valley, which in turn beheaded and reversed flood flow on diverging flood flow channels to create the present day north-oriented Smith River tributary valleys. Evidence for former diverging and converging south-oriented flood flow channels can be seen along present drainage divides between the various Smith River tributaries. For example the Porcupine Creek-Trout Creek drainage divide north and west of Millegan is crossed by a high level through valley, which was eroded by a southeast-oriented converging flood flow channel prior to the reversal  of flood flow that eroded the deep west-northwest oriented Porcupine Creek valley (see figure 4 for a detailed topographic map of the region).

Figure 4 provides a detailed topographic map of the Porcupine Creek-Trout Creek drainage divide area seen in less detail in figure 3 above. Millegan is the small town located in the figure 4 southeast quadrant. Trout Creek flows in a northeast direction through Millegan and joins the north-oriented Smith River east of the figure 4 map area. Coal Creek is an east-oriented Trout Creek tributary originating in section 25. Porcupine Creek is the northwest and west-northwest oriented stream flowing to the figure 4 northwest corner. Note the north-south oriented through valley just west of the corner of sections 13, 18, 19, and 24 linking the Porcupine Creek valley with the Coal Creek valley. The west-oriented stream in the figure 4 southwest quadrant is East Fork, which west of figure 4 flows to north-oriented Government Creek, which in turn flows to north-northeast oriented Hound Creek. The figure 4 map contour interval is 40 feet and the through valley floor elevation is between 5440 and 5480 feet. The hill to the east of the through valley rises to 5898 feet while the hill to the west rises to 6031 feet meaning the through valley is at least 420 feet deep. The through valley is a water eroded feature and was eroded as a south-oriented flood flow channel prior to headward erosion of the deep west-northwest oriented Porcupine Creek valley and also before headward erosion of the deep Hound Creek valley and of the deep Missouri River valley north and west of the figure 4 map area. Probably the south-oriented flood flow was moving to what was then a south-oriented flood flow channel on the present day north-oriented Smith River alignment. Headward erosion of the deep Missouri River valley north and west of the figure 4 map area beheaded south-oriented flood flow channels flowing across the figure 4 map area and triggered flood flow reversals that resulted in headward erosion of the deep northeast-oriented Trout Creek valley and subsequently headward erosion of the west-northwest oriented Porcupine Creek valley. Note also in the section 25 northwest corner an east-west oriented through valley linking the east-oriented Coal Creek valley with the west-oriented East Fork valley. This second through valley has a floor elevation at the drainage divide of between 5360 and 5400 feet and is slightly deeper than the first through valley. This second through valley is evidence of diverging and converging flood flow channels that were once eroded into an erosion surface equivalent in elevation to the highest figure 4 elevations today and may have moved south-oriented flood water from west of the figure 4 map area to the newly beheaded and reversed flood flow channels east of the figure 4 map area (remember Missouri River valley and tributary valley headward erosion beheaded south-oriented flood flow channels one at a time usually from east to west).

Figure 5: Trout Creek-Smith River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

   

Figure 5 illustrates the Trout Creek-Smith River drainage divide area south and slightly east of the figure 3 map area and includes overlap areas with figure 3. The Smith River meanders in a north direction near the figure 5 east edge. Millegan is the small town located in the figure 5 northeast quadrant. Trout Creek flows in a north-northeast and northeast direction through Millegan to join the Smith River near the figure 5 northeast corner. Mud Gulch is an east oriented Smith River tributary located south of Millegan. Hound Creek flows in a northeast and north direction from the figure 5 west center to the figure 5 north edge (west half). Government Creek is the north-oriented tributary flowing to the figure 5 north edge just east of Hound Creek and joins Hound Creek north of the figure 5 map area. Pine Coulee is the northwest, north, and west-northwest Hound Creek tributary located south of Government Creek. Crooked Creek is the north-oriented Hound Creek tributary flowing just west of the Cascade-Meagher county line. Note how the north-oriented Pine Coulee valley segment is aligned with the north-oriented Government Creek valley and how the two valley segments are linked by a north-south oriented through valley. The through valley is evidence of a south-oriented flood flow channel that once flowed across the region. The flood flow channel was dismembered by crustal warping that raised the region south of figure 5 and by the resulting flood flow reversal that eroded the deep north-oriented Hound Creek valley, which beheaded and reversed the south-oriented flood flow to erode the north-oriented Government Creek valley and the west-northwest oriented Pine Coulee valley. In the figure 5 east half note the Trout Creek-Mud Gulch drainage divide area which contains at least two deep through valleys. The figure 5 map contour interval is 50 meters and the through valley floor elevations at the drainage divide is between 1550 and 1600 meters. The hill between Millegan and Mud Gulch rises to more than 1700 meters and the hill to the southwest of Mud Gulch rises to more than 1850 meters. In other words the through valleys are at least 100 meters deep and provide evidence of multiple flood flow channels moving flood water between the Trout Creek valley and the Smith River valley. Flood waters were probably coming from north and west of the Trout Creek valley, which was being eroded at the time and which probably occurred when south-oriented flood flow on the Smith River alignment was being reversed to flow in a north direction and there was still south-oriented flood flow moving on a high level surface to the west. Headward erosion of deep valleys during the flood flow reversal process beheaded the east- and southeast-oriented flood flow to the actively eroding Trout Creek valley and eroded the north-oriented Hound Creek valley and tributary valleys.

Figure 6: Detailed map of Trout Creek-Mud Gulch drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 6 provides a detailed topographic map of the Trout Creek-Mud Gulch drainage divide area seen in less detail in figure 5 above. The Smith River meanders in a north direction along and across the figure 6 east edge. Trout Creek flows in a northeast, northwest, and northeast direction from the figure 6 west edge (just south of center) to the figure 6 north edge (west half). Mud Gulch originates in section 17 and drains in an east and southeast direction to join the north-oriented Smith River as a barbed tributary in the section 24 northwest corner. Two Creek is the east-southeast and east-northeast oriented tributary joining the Smith River at about the same point as where Mud Gulch joins the Smith River and One Creek is the Two Creek tributary between Two Creek and Mud Gulch. Note in the section 8 southwest quadrant a northwest-southeast oriented through valley linking a northwest-oriented Trout Creek tributary with a southeast-oriented Mud Gulch tributary valley. The through valley is one of several similar through valleys crossing the Trout Creek-Mud Gulch drainage divide. The figure 6 map contour interval is 40 feet and through valley floor elevation at the drainage divide (where the two unimproved roads meet) is 5107 feet. The hill in section 9 rises to 5612 feet and the hill near the figure 6 southwest corner rises to 6365 feet. Using the eastern elevation the through valley is at least 500 feet deep and was eroded by southeast-oriented flood flow prior to headward erosion of the deeper northeast-oriented Trout Creek valley, which beheaded and reversed the southeast-oriented flood flow channel to erode the northwest-oriented Trout Creek tributary valley. Another through valley of similar depth can be seen in section 18 and a somewhat shallower through valley is located in the section 8 east half. These three through valleys provide evidence of multiple converging east- and southeast-oriented flood flow channels crossing what is now the Trout Creek-Mud Gulch drainage divide. In section 16 there is a through valley crossing the Mud Gulch-One Creek drainage divide. That through valley elevation at the drainage divide is between 4960 and 5000 feet and the hill to the east rises to 5103 feet, meaning the through valley is at least 100 feet deep. Evidence for another through valley can be seen in section 21 crossing the One Creek-Two Creek drainage divide. These through valleys as a group provide evidence of a dismembered south and southeast-oriented flood flow channel, which once moved flood water to the south-oriented flood flow channel on the Smith River alignment. The flood flow channel was dismembered from south to north by headward erosion of the Two Creek valley, One Creek valley, Mud Gulch valley, and Trout Creek valley with headward erosion the Hound Creek tributary valleys dismembering it further to the north and west.

Figure 7: Crooked Creek-Freeman Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 7 illustrates the Crooked Creek-Freeman Creek drainage divide area south and west of the figure 5 map area and includes overlap areas with figure 5. The north-south oriented Cascade County-Meagher County boundary is shown and labeled and turns in a west direction in the figure 7 southwest quadrant and the Meagher County-Lewis and Clark County can be seen in the figure 7 southwest corner region. Hound Creek is formed in the figure 7 northwest quadrant at the confluence of southeast oriented East Fork, northeast oriented Middle Creek, and north-oriented Elk Creek and then flows in a northeast direction to the figure 7 north edge (near the Cascade-Meagher County boundary). East of north-oriented Elk Creek and flowing just west of the county line is north-oriented Crooked Creek. Pine Coulee is the northwest, north, and west-northwest oriented tributary from the east joining Hound Creek at the figure 7 north edge. The north and north-northeast oriented stream east of Pine Coulee and flowing to the figure 7 north edge (near northeast corner) is Trout Creek. Headwaters of east oriented Mud Gulch can be seen just south of the figure 7 northeast corner. The east and southeast oriented stream flowing to the figure 7 southeast corner is Freeman Creek, which has an east and southeast oriented North Fork and an east oriented South Fork, both of which can be seen in the figure 7 southeast quadrant. South and east of the figure 7 map area Freeman Creek flows to east-oriented Rock Creek, which then joins the north-oriented Smith River. The southwest and south-oriented stream flowing to the figure 7 south edge (west of center) is the North Fork Rock Creek and its southeast-oriented tributary is Butte Creek. South of the figure 7 map area the North Fork Rock Creek flows to southeast, northeast, and east-oriented Rock Creek. Note the numerous through valleys linking the various drainage basins seen. For example a high level through valley links the north-oriented Trout Creek valley with the southeast-oriented North Fork Freeman Creek valley. A west to east oriented through valley links the north-oriented Crooked Creek valley with the east- and southeast-oriented North Fork Freeman Creek valley. A short distance to the north a west to east oriented through valley links the northwest-oriented Pine Coulee headwaters valley with the north-oriented Trout Creek valley. In the figure 7 southwest quadrant a northwest-southeast oriented through valley links the north-oriented Elk Creek valley with the southeast-oriented Butte Creek valley. Each of these through valleys (and other through valleys not mentioned) provides evidence of south-oriented diverging and converging flood flow channels that once crossed the figure 7 map area. The flood flow channels were dismembered in sequence from south to north and from east to west by the massive flood flow reversals caused by crustal warping of the region and by headward erosion of the much deeper Missouri River valley north of the figure 7 map area.

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

 

Figure 8 provides a detailed topographic map of the Crooked Creek-North Fork Freeman Creek drainage divide area seen in less detail in figure 7 above. Crooked Creek originates in section 31 and flows in a northwest and north direction to the figure 8 north edge (near northwest corner) and north of figure 8 flows to Hound Creek. The North Fork Freeman Creek originates section 32 and flows in an east and southeast direction to the figure 8 east edge (south of center) and east and south of the figure 8 flows to Freeman Creek, which flows to Rock Creek, which then flows to the Smith River. Note in section 32 the through valley linking the North Fork Freeman Creek headwaters valley with the northwest-oriented Crooked Creek headwaters valley. The figure 8 map contour interval is 40 feet and the through valley floor elevation at the drainage divide is shown as being 6503 feet. The hill at the north edge of section 32 has an elevation of 6818 feet while elevations rise to more than 7000 feet in the section 32 southwest quadrant. In other words the through valley is more than 300 feet deep and is evidence of a southeast-oriented flood flow channel that once moved flood water to the south-oriented flood flow channel on the Smith River alignment. North Fork Rock Creek originates in sections 5 and 6 and flows in a south direction to the figure 8 south edge (west of center) and south of figure 8 flows to east-oriented Rock Creek, which then flows to the north-oriented Smith River. Note in the west half of section 6 a north-south oriented through valley linking the north-oriented Crooked Creek valley with the south-oriented North Fork Rock Creek valley. The through valley floor elevation at the drainage divide is between 6720 and 6760 feet, which is at least 200 feet higher that Crooked Creek-North Fork Freeman Creek through valley floor elevation. The high point in section 5 is shown as being 7097 feet and in the west half of section 1 elevations rise to more than 7080 feet, meaning the Crooked Creek-North Fork Rock Creek through valley is at least 320 feet deep. The through valley is also a former flood flow channel and the Crooked Creek headwaters valley in section 36 was where two south-oriented flood flow channels once diverged, with one channel flowing in an east and southeast direction to the North Fork Freeman Creek valley and the other flowing in a south direction to the North Fork Rock Creek valley. Headward erosion of the deeper North Fork Freeman Creek flood flow channel in time probably beheaded south-oriented flood flow to the south-oriented North Fork Rock Creek flood flow channel, which may account for the present day through valley elevation differences.

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

 

Figure 9 illustrates the Elk Creek-Rock Creek drainage divide area south and west of the figure 7 map area and includes overlap areas with figure 7. County lines are shown and labeled. Crooked Creek originates in the Cascade County southeast corner and flows in a north direction near the county line to the figure 9 north edge. Elk Creek is located west of Crooked Creek and flows in a north direction to the figure 9 north edge (east of center). Middle Creek originates near the southeast end of Shellrock Ridge and flows in a northeast direction through Middle Creek Lake to the figure 9 north edge west of center (a power line follows it). Rock Creek originates in the Jim Ball Basin in the figure 9 south center region and flows in a southwest direction before making a U-turn to flow in an east-northeast and east-southeast direction to the figure 9 east edge (just north of southeast corner). The North Fork Rock Creek originates east of Squaw Teat in the figure 9 east center area and flows in a southwest and south direction to join Rock Creek. Butte Creek is a southeast-oriented tributary flowing to south-oriented North Fork Rock Creek. North of the Jim Ball Basin are headwaters of southwest, west, and southwest-oriented Beaver Creek, which flows to the figure 9 southwest corner and then to the north-oriented Missouri River (west of the figure 9 map area). Again note the large number of high level through valleys crossing the drainage divides. The through valley linking the north-oriented Elk Creek valley with the southeast-oriented Butte Creek valley is better illustrated in a detailed topographic map in figure 10 below. Note how in the Jim Ball Basin area Rock Creek headwaters are linked by a through valley with west-oriented Pike Creek, which flows to southwest-oriented Beaver Creek. The through valley provides evidence of a flood flow channel that was dismembered by headward erosion of deep valleys from opposite directions. High level through valleys link the northeast-oriented Middle Creek valley with south-oriented Beaver Creek tributary valleys and suggest the south-oriented flood water came from north of figure 9. The flood flow reversal responsible for the north-oriented Hound Creek tributaries north of the figure 9 map area was at least in part caused by crustal warping that raised elevations in this figure 9 map area. However, the southwest-oriented Beaver Creek valley probably eroded headward from a south-oriented flood flow channel on the present day north-oriented Missouri River alignment, which means the flood flow reversal in that valley was caused by headward erosion of the much deeper Missouri River valley north and west of figure 9.

Figure 10: Detailed map of Elk Creek-Butte 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 Elk Creek-Butte Creek drainage divide area seen in less detail in figure 9 above. Butte Creek flows from sections 11 and 10 in a southeast direction to the figure 10 southeast corner and south and east of figure 10 flows to south oriented North Fork Creek with water eventually reaching the north-oriented Smith River. Beaver Creek originates in section 9 and flows in a south and southwest direction to the figure 10 southwest corner with water eventually reaching the north-oriented Missouri River. Elk Creek originates north of Elk Ridge in sections 2, 3, 4, 9 (northeast corner), and 10 (north half) and flows to the figure 10 north edge (west of center) and north of figure 10 flows to north-northeast oriented Hound Creek. Note in the northeast corner of section 10 and northwest corner of section 11 a northwest-southeast oriented through valley linking the north-oriented Elk Creek valley with the southeast-oriented Butte Creek valley. The figure 10 map contour interval is 40 feet and the through valley elevation at the drainage divide is between 6560 and 6600 feet. Elevations greater than 7100 feet can be found on either side of the through valley. Also note where the Meagher-Lewis and Clark County line crosses the section 4-section 9 boundary a northeast-southwest oriented through valley linking the north-oriented Elk Creek valley with the south and southwest-oriented Beaver Creek valley. This second through valley elevation at the drainage divide is shown as being 6725 feet, which is at least 125 feet higher than the Elk Creek-Butte Creek through valley. These two through valleys were eroded by diverging south-oriented flood flow channels, which diverged from a south-oriented flood flow channel on the Elk Creek alignment. The eastern diverging flood flow channel moved flood waters to a south-oriented flood flow channel on the present day Smith River-Shields River alignment and then to the actively eroding Yellowstone River valley. The western diverging flood flow channel moved flood water to a south-oriented flood flow channel on the present day Missouri River alignment which at that time may have been eroded headward from the present day west and northwest-oriented Snake River valley (just west of Yellowstone National Park). Deeper erosion of the eastern diverging flood flow channel may have beheaded flood flow to the western diverging flood flow channel. Crustal warping that raised figure 10 map area and adjacent region elevations combined with headward erosion of the deep northeast-oriented Missouri River valley beheaded and reversed a flood flow channel on the Hound Creek-Elk Creek valley alignment, which ended south-oriented flood flow to the figure 10 diverging channels.

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.