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 Two Medicine River-Birch Creek drainage divide area landform origins east of the mountains in Glacier and Pondera 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 then 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 Two Medicine River-Birch Creek drainage divide area landform evidence east of the mountains in Glacier and Pondera Counties, Montana will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm (see link to paradigm related essay in menu at top of page). This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Figure 1: Two Medicine River-Birch 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 Two Medicine River-Birch Creek drainage divide area location map and shows a region in northwest Montana with the southeast corner of British Columbia and a strip of southern Alberta to the north. Glacier National Park is located in Montana directly south of the British Columbia-Alberta border. The west to east continental divide defines the British Columbia-Alberta border in Canada and then extends in roughly a south-southeast direction through Glacier National Park to the figure 1 south edge (east of center). Montana drainage routes east of the continental divide, including the Milk River which flows across southern Alberta, are Missouri River tributaries with water eventually reaching the Gulf of Mexico. The Missouri River can be seen in the figure 1 southeast corner flowing in a northeast direction at Great Falls. Major east-oriented Missouri River tributaries seen in figure 1 (from south to north) include the Sun River, Teton River, Marias River (formed at the confluence of Cut Bank Creek and the Two Medicine River, with Birch Creek being a Two Medicine River tributary), and the Milk River. North of the Milk River in Alberta is the Saskatchewan River drainage basin and the major South Saskatchewan River tributary seen is the Oldman River with its St Mary and Belly River tributaries. Water in the Saskatchewan River drainage basin eventually reaches Hudson Bay. West of the continental divide is the Flathead River drainage basin where the Middle and South Forks of the Flathead River flow in northwest and north-northwest directions to the Glacier National Park south boundary before turning in a west direction to join the south-southeast oriented North Fork Flathead River and then to flow in a south direction to Flathead Lake and to the figure 1 south edge. Water in the Flathead River flows to northwest-oriented Clarks Fork (seen in the figure 1 southwest corner) and eventually reaches the Columbia River and the Pacific Ocean. The Two Medicine River originates in the southeast corner of Glacier National Park near the town of East Glacier Park and flows in an east direction to join Cut Bank Creek and to form the Marias River (which flows to Lake Elwell). Birch Creek is a northeast, east, and northeast oriented tributary originating in the mountains south and east of East Glacier Park and joining the Two Medicine River near its confluence with Cut Bank Creek. The study region for this essay is located south of the Two Medicine River, north of Birch Creek, and east of the Rocky Mountain front. The Two Medicine River-Birch Creek drainage divide area landform origins near the continental divide, Glacier, Pondera, and Teton Counties essay describes the region directly to the west. The Cut Bank Creek-Two Medicine River drainage divide area landform origins, Glacier County essay describes the region directly to the north. These and other regional essays can be found by selecting the Marias River from the sidebar category list.

• Topographic map evidence for landform origins in the Two Medicine River-Birch Creek drainage divide area east of the mountains is interpreted in this essay in the context of immense south and southeast oriented melt water floods derived from a rapidly melting thick North American ice sheet, which had been located in a deep “hole.” At first the ice sheet had stood high above the surrounding continental surface and the deep “hole” gradually evolved as deep glacial erosion scoured the bedrock underneath the ice sheet and as crustal warping altered the non glaciated continental surface. Today the upper Missouri River drainage basin in Montana and northern Wyoming and the Saskatchewan River drainage basin in southwest Alberta represent the deeply eroded deep “hole” southwest wall and crests of high Rocky Mountain ranges roughly paralleling the east-west continental divide represent what is left of the deep “hole’s” southwest rim. The deep “hole” was an ice sheet created landscape feature and did not exist at the time the ice sheet formed. At that time the Rocky Mountains did not stand high as they do today and initially south and southeast oriented melt water floods could flow easily along what are today crests of high mountains forming the east-west continental divide. Initially flood waters flowed roughly along the continental divide alignment in southeast and south directions from Canada across Montana, Wyoming, and Colorado into New Mexico and further. Rocky Mountain uplift occurred as gigantic melt water floods flowed across the region and proceeded from the south to the north. The immense south-oriented melt water floods were diverted both to the east and to the west as rising mountains and plateaus blocked southward flood flow and as deep southeast and southwest oriented valleys eroded headward toward the present day continental divide. Eventually a combination of crustal warping that was raising the Rocky Mountains and plateaus in Wyoming and of ice sheet melting that was lowering the ice sheet surface (especially along and near the ice sheet southwest margin) created a situation where the massive ice-marginal melt water floods from further north were being captured by large east- and northeast-oriented valleys eroding headward from space in the deep “hole” being opened up as the ice sheet melted. Space in the deep “hole” was being opened as giant supra-glacial melt water rivers carved gigantic south-oriented ice-walled (and later bedrock-floored) canyons into the decaying ice sheet surface.

• Of particular importance to the Montana and northern Wyoming upper Missouri River drainage basin history was a giant southeast and south oriented ice-walled canyon in present day Saskatchewan, North Dakota, and South Dakota. In time this huge ice-walled canyon became an ice-walled and bedrock-floored canyon and detached the ice sheet’s southwest margin. Today the Missouri Escarpment in Saskatchewan, North Dakota, and South Dakota is what remains of that giant canyon’s southwest and west wall. The present day east-oriented Missouri River valley in northern Montana represents the last east-oriented valleys eroded headward from the large southeast  and south oriented ice-walled canyon in the present day United States. East-oriented Missouri River tributary valleys eroded headward in sequence from southeast to northwest from that actively eroding valley. For example in the figure 1 map area Sun River valley headward erosion occurred prior to Teton River valley headward erosion which beheaded south and southeast oriented flood flow to the newly eroded Sun River valley. Next Marias River valley headward erosion beheaded flood flow routes to the newly eroded Teton River valley and Milk River valley headward erosion beheaded flood flow routes to the newly eroded Marias River valley. In the case of Marias River tributaries Birch Creek valley headward erosion occurred before Badger Creek headward erosion which beheaded flood flow to the newly eroded Birch Creek valley and Two Medicine River valley headward erosion beheaded south-oriented flood flow to the newly eroded Badger Creek valley. At approximately the same time as these east-oriented valleys were being eroded east of the continental divide similar headward erosion of deep valleys was occurring west of the continental divide. The northwest-oriented Middle Fork Flathead River valley and the north-northwest oriented South Fork Flathead River valley were eroded by massive reversals of flood flow on what had been south-oriented flood flow channels. The flood flow reversals occurred as deep west-oriented valleys beheaded south-oriented flood flow channels. The northwest-oriented Clark Fork valley was eroded by a massive flood flow reversal in what had been a major southeast-oriented melt water flood flow channel and the deep south-oriented Flathead River valley eroded headward along what had been a south-oriented flood flow channel.

• The discussion in this essay is concerned primarily with water eroded landforms, however several of the topographic maps in this essay illustrate what may be landscape features formed by mountain glaciers some of which may have advanced onto the plains. While my discussions will generally ignore these glacial landscape features they do exist and provide evidence of at least local glaciation in various Two Medicine River-Birch Creek drainage divide areas. The local glaciation occurred after the thick ice sheet rapid melt down ended and modified to a limited degree a landscape that had been created by immense south and southeast oriented melt water floods during the thick ice sheet rapid melt down. Why would local glaciers develop in this region after the thick ice sheet rapid melt down ended? Remember the giant south-oriented ice-walled and bedrock-floored canyons that captured the ice-marginal melt water floods from further to the north. Many of the huge melt water rivers flowing on the floors of those canyons were emptying into what was an evolving Mississippi River drainage basin with much of the massive flood flow moving to the Gulf of Mexico. Movement of these huge melt water floods into the Gulf of Mexico pushed warm water into the Atlantic Ocean where ocean currents carried the warm waters north and warmed the northern hemisphere climate. As the northern hemisphere climate became warmer the thick ice sheet melting increased and the south-oriented flood flow increased, which further warmed the northern hemisphere climate. This ever warming northern hemisphere climate continued until large north-oriented ice-walled and bedrock-floored canyons began to be carved into the ice sheet surface and began to intersect the south-oriented ice-walled and bedrock-floored canyons. The northern ice-walled and bedrock-floored canyons had much shorter routes to the ocean, which in many cases was the North Atlantic Ocean and began to capture the gigantic south-oriented melt water floods. The resulting diversion of the immense south-oriented melt water floods from the Gulf of Mexico to the North Atlantic Ocean completely changed the oceanic circulation pattern. Instead of warm water moving north cold water began to move south and the northern hemisphere ceased to become warmer and began to become colder and colder. In time the immense north-oriented melt water floods began to freeze on the floors of what had become north-oriented ice-walled and bedrock-floored canyons and created a thin ice sheet with remnants of the thick ice sheet embedded in it. This cooling of the northern hemisphere climate also meant alpine glaciers could form on the newly uplifted and deeply eroded Rocky Mountains and other high North American continent regions. In time the thin ice sheet and many of the alpine glaciers gradually melted, although without the gigantic melt water flood events that the rapidly melting thick ice sheet had produced.

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

 

Figure 2 provides a detailed location map for the Two Medicine River-Birch Creek drainage divide area. County boundaries are shown and county names are given with Pondera County south of Glacier County and Teton County south of Pondera County. The western boundary of Glacier, Pondera, and Teton Counties is defined by the east-west continental divide and Flathead County is west of the continental divide. Glacier National Park is shown straddling the continental divide in the figure 2 west half with the Blackfeet Indian Reservation being located east of Glacier National Park. National Forest lands in the mountain areas surrounding Glacier National Park are also shown. The Two Medicine River originates near Lone Walker Mountain (on the continental divide just south of figure 2 center) and flows to East Glacier Park and then in roughly an east direction to join Cut Bank Creek near the figure 2 east center edge. Birch Creek originates near Gateway Pass (located along continental divide near figure 2 south edge) and flows in roughly a northeast direction to join the Two Medicine River just before the Two Medicine River joins Cut Bank Creek. Between the Two Medicine River and Birch Creek is Badger Creek, which originates near Badger Pass (on continental divide slightly north and west of Gateway Pass) and flows in a northeast direction to join the Two Medicine River in the southeast Blackfeet Indian Reservation. The Two Medicine River-Birch Creek drainage divide area landform origins near the continental divide essay describes landform origins in the Two Medicine River, Badger Creek, and Birch Creek headwaters area, which is located in the north-northwest to south-southeast trending Rocky Mountains. The study region for this essay is east of the mountain front and is located almost entirely in the southern Blackfeet Indian Reservation land area. The hypothesis presented in this essay is the study region was eroded by massive south and southeast oriented melt water floods, which were first captured by headward erosion of a deep northeast and east oriented Birch Creek valley. Subsequently headward erosion of a deep northeast-oriented Badger Creek valley and its northeast-oriented tributary valleys beheaded the south and southeast oriented flood flow to the newly eroded Birch Creek valley and its actively eroding tributary valleys. Next Two Medicine River valley headward erosion beheaded south and southeast oriented flood flow routes to the newly eroded Badger Creek valley and its actively eroding tributary valleys. Still later Cut Bank Creek valley headward erosion beheaded south- and southeast-oriented flood flow routes to the newly eroded Two Medicine River valley and its actively eroding tributary valleys as described in the Cut Bank Creek-Two Medicine River drainage divide area landform origins essay.

Figure 3: East end of the Two Medicine River-Birch Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 3 illustrates the east end of the Two Medicine River-Birch Creek drainage divide area. The Two Medicine River is labeled and flows from the figure 3 northwest corner in an east, southeast, east-northeast, north, east, east-southeast direction to the figure 3 east edge (north half). Kipps Coulee is the east-northeast oriented tributary joining the Two Medicine River near Hagans Crossing (in figure 3 northwest quadrant). Blacktail Creek flows in east direction along the south edge of the figure 3 southwest quadrant and then flows south of the figure 3 map area to join north-northeast oriented Birch Creek, which flows the figure 3 south edge (east half) to join the Two Medicine River near the figure 3 east edge. Rocky Ridge Coulee is the east-northeast and south oriented tributary draining from the figure 3 west edge (south half) to Alkali Lake  and then to Birch Creek near the figure 3 east edge. Note how there is a north-northwest to south-southeast oriented through valley linking the Two Medicine River valley near Hagans Crossing with the Alkali Lake basin. The figure 3 map contour interval is 20 meters and through valley floor elevation at the drainage divide is between 1180 and 1200 meters. Elevations on the ridge to the east of the through valley rise to more than 1240 meters while on the ridge to the west elevations rise to more than 1300 meters meaning the through valley is at least 40 meters deep and probably is deeper. The through valley is a water eroded landscape feature and was eroded as a south-oriented flood flow channel prior to headward erosion of Two Medicine River valley. Another well-defined north-south oriented through valley can be seen along the county line near the figure 3 west center edge. The floor of that second through valley has an elevation at the drainage divide of between 1240 and 1260 meters. The ridge to the east rises to at least 1300 meters while the ridge just barely seen in figure 3 to the west rises even higher. This second higher level through valley is also at least 40 meters deep and may be deeper and is evidence of another south-oriented south flood flow channel prior to headward erosion of the Kipps Coulee valley (and the subsequent headward erosion of the Two Medicine River valley). A close look at the figure 3 map reveals additional shallower through valleys and study of more detailed topographic maps reveals even more through valleys and additional details about the through valleys. For purposes of this essay the important thing to remember is before the east and northeast oriented valleys were eroded headward across the region there were multiple south-oriented flood flow channels crossing the region. The south- and southeast-oriented flood flow channels were captured in sequence from south to north by headward erosion of the northeast- and east-oriented valleys seen today.

Figure 4: Two Medicine River-Badger Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 4 illustrates the Two Medicine River-Badger Creek drainage divide area west of the figure 3 map area and includes a small overlap area with figure 3. The Two Medicine River flows in a northeast direction from the figure 4 west edge (south half) to near the figure 4 north edge (near northeast corner) and then turns to flow in a southeast direction to the figure 4 east edge (south of northeast corner). Badger Creek flows in a northeast direction from the figure 4 south edge (west of center) to join the Two Medicine River near the figure 4 east edge. Piegan is a small community located near where the highway crosses Badger Creek. Whitecalf Coulee is a northeast-oriented tributary joining Badger Creek near Piegan. Kipps Coulee headwaters can be seen south and east of Badger Creek and drain in a northeast direction to the figure 4 east center edge. Note how the Kipps Coulee valley is linked by through valleys with a north-oriented Badger Creek tributary valley (south of Piegan). Just north of the highway is a west to east oriented through valley with an elevation at the drainage divide of between 1240 and 1260 meters (the map contour interval is again 20 meters). Elevations to the north rise to more than 1300 meters while to the south-west elevations rise to 1344 meters. South and west of the highway is a southwest to northeast oriented through valley with a floor elevation at the drainage divide of between 1280 and 1300 meters. The north-oriented tributary valley, which will be seen more completely and in detail in figures 8 and 9 below, is the north end of a deep north-south oriented through valley linking the Badger Creek and Birch Creek valleys. The through valleys linking the northeast-oriented Kipps Coulee valley with this north-south oriented through valley provide evidence that for a time flood waters were being captured by headward erosion of the actively eroding Kipps Coulee valley, but headward erosion of a deep south-oriented tributary valley (or flood flow channel) from the newly eroded Birch Creek valley beheaded at least two flood flow routes to the newly eroded Kipps Coulee valley. Orientations of the valleys suggest headward erosion of the different valleys were competing with each other for the flood waters, with the deeper valleys capturing the flood flow. Another interesting north-south oriented through valley can be seen west of Piegan and just north of Whitecalf Coulee. A secondary road junction just north of the deep north-south oriented through valley is shown as having an elevation of 1284 meters. Elevations on either side of the through valley rise to more than 1320 meters suggesting the through valley is approximately 40 meters deep. The through valley links a northeast-oriented Two Medicine River valley with the Whitecalf Coulee valley and was eroded by south-oriented flood flow prior to headward erosion of the northeast-oriented-oriented Two Medicine River tributary valley, which occurred slighty in advance of Two Medicine River valley headward erosion which beheaded flood flow to the newly eroded tributary valley.

Figure 5: Detailed map of Two Medicine River-Whitecalf Coulee drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 5 illustrates a detailed topographic map of the Two Medicine River-Whitecalf Coulee drainage divide area seen in less detail in figure 4. The Two Medicine River flows in a northeast direction from the figure 5 west edge (south of center) to the figure 5 north edge (west of center). Badger Creek flows in a northeast direction across the figure 5 southeast corner. Whitecalf Coulee drains in a northeast direction from the figure 5 south center edge to the figure 5 east edge (south of center). Note in the section 21 southeast quadrant the north-south oriented through valley described in figure 4. The through valley floor elevation at the drainage divide is given at the road intersection as 4213 feet (the figure 5 map contour interval is 20 feet). The hill in section 22 to the east rises to 4346 feet while the hill to the west in section 21 rises to at least 4340 feet meaning the through valley is at least 127 feet deep and probably was deeper when eroded. The through valley was eroded by south oriented flood flow moving to what was probably an actively eroding Whitecalf Coulee valley. At that time elevations north of the Whitecalf Coulee valley were at least as high as the highest figure 5 elevations today and south-oriented flood waters were eroding deep channels into that high level surface. What was then an actively eroding Two Medicine River valley was located east and north of the figure 5 map area. A major (and unnamed) northeast-oriented tributary valley next eroded headward from the actively eroding Two Medicine River valley and captured the south- and southeast-oriented flood flow. The northeast-oriented tributary can be seen flowing to the figure 5 northeast corner and has multiple east-oriented tributaries in sections 9, 10, 15, and 16. Note how those tributary valleys have eroded what appears to be a small-scale anastomosing channel complex in sections 9, 10, 15, and 16. Headward erosion of the deep northeast-oriented Two Medicine River valley across the figure 5 map area subsequently captured the southeast-oriented flood flow moving to the east-oriented anastomosing channel complex and then to the northeast-oriented Two Medicine River tributary valley. Shallow through valleys can be seen along the ridge in sections 8 and 18 separating the Two Medicine River valley from the east-oriented anastomosing channel complex. Generally these through valleys are defined by only one or two contour lines on a side suggesting flood flow to the east-oriented anastomosing channel complex had not had time to erode deep channels before Two Medicine River valley headward erosion beheaded the flood flow routes.

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

 

Figure 6 illustrates the Little Badger Creek-Badger Creek drainage divide area west and south of the figure 4 map area and includes an overlap area with figure 4. The Two Medicine River flows in an east-southeast direction from the figure 6 northwest corner to join its east-oriented South Fork and then to flow in an east-northeast and east direction to the figure 6 north edge (near northeast corner). Little Badger Creek is formed at the confluence its North and South Forks in the figure 6 southwest quadrant and then flows in a northeast direction to join the Two Medicine River near the figure 6 northeast corner. Badger Creek flows in a north direction from the figure 6 south edge (west of center) and then in an east direction across the figure 6 south center region before turning to flow in a northeast direction to the figure 6 east center edge. The northeast-oriented stream in the figure 6 southeast corner is the North Fork Whitetail Creek. Note how just east of where the highway crosses Little Badger Creek there is a through valley linking the northeast-oriented Badger Creek valley with the valley of an east, east-northeast, and east oriented Badger Creek tributary. The map contour interval is 20 meters in the figure 6 east half and 50 meters in the figure 6 west half. The through valley floor elevation at the drainage divide is between 1380 and 1400 meters. The ridge east of the through valley rises to more than 1440 meters and much higher elevations can be found west of the highway. The through valley is at least 40 meters deep. Also note how the Badger Creek tributary drains this through valley and begins almost on the edge of the adjacent northeast-oriented Little Badger Creek valley. This evidence suggests the Little Badger Creek and Badger Creek valleys were eroded as channels in an anastomosing channel complex where headward erosion of the deeper Little Badger Creek valley beheaded a diverging east-oriented flood flow channel to the newly eroded Badger Creek valley. Also note in the figure 6 west half there is a broad, but shallow northwest-southeast oriented through valley crossing the Two Medicine River-Little Badger Creek drainage divide. Elevations are tricky in this area although east of the highway the drainage divide is marked by areas where elevations exceed 1400 meters and then are slightly to the west. The through valley extends in a southeast direction as an extension of the east-southeast oriented Two Medicine River valley segment seen in the figure 6 northwest corner. The change in contour intervals makes this through valley difficult to see both on figure 6 and on figure 7, which is a more detailed topographic map of the valley’s southeast end.

Figure 7: Detailed map of Little Badger Creek-Badger Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 7 provides a detailed map of the Little Badger Creek-Badger Creek drainage divide area seen in less detail in figure 6 above. Little Badger Creek flows in a northeast direction from the figure 7 west center edge to the figure 7 north center edge. Badger Creek flows from the figure 7 south edge (west half) in a northeast and east direction to the figure 7 east edge (south half). An unnamed east-northeast oriented Two Medicine River tributary flows in an east-northeast direction between Little Badger Creek and Badger Creek to the figure 7 east edge (just south of northeast corner). This Two Medicine River tributary originates in section 22 (near the figure 7 west edge) and flows across the north half of section 23 and the south half of section 13  and of section 18 before turning to flow in a northeast direction to the figure 7 east edge. Note how this Two Medicine River tributary flows adjacent to the Little Badger Creek valley and is linked with that valley by northwest-southeast oriented through valleys. The map contour interval in the figure 7 east half is 20 feet and is 40 feet in the west half again making it difficult to determine elevations. However in section 13 there are several through valleys defined by two 20-foot contour lines on each side. The tributary has eroded a deep east-oriented valley, or water gap, through the ridge in the section 18 southwest quadrant with the valley floor elevation being between 4500 and 4520 feet. Elevations on each side of the valley rise to more 4730 feet meaning the valley is more than 110 feet deep. At the time the valley was eroded the deep Little Badger Creek valley did not exist and elevations to the west and north of the ridge through which the valley is eroded were at least as high as the ridge top today. Note also in section 23 another northwest-southeast oriented through valley roughly following the highway linking the Little Badger Creek valley with the Badger Creek valley. These northwest-southeast oriented through valleys are extensions of a northwest-southeast oriented through valley linking the Two Medicine River valley with the Little Badger Creek valley, the southeast end of which can be seen in the figure 7 northwest quadrant. The east-southeast oriented Two Medicine River valley segment seen in the figure 6 northwest quadrant points directly to this southeast-oriented through valley suggesting it was eroded headward along the northwest extension of the southeast-oriented through valley. The through valleys were eroded by southeast-oriented flood flow moving across the figure 7 map area as the deep east- and northeast-oriented valleys eroded headward into the region. Headward erosion of the Badger Creek valley occurred first, the unnamed east- and northeast-oriented Two Medicine River valley eroded headward next, and then Little Badger Creek valley headward erosion beheaded flood flow to the newly eroded unnamed Two Medicine River tributary valley and to the newly eroded Badger Creek valley.

Figure 8: Whitetail Creek-Blacktail Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 8 illustrates the Whitetail Creek-Blacktail Creek drainage divide area located south and east of the figure 4 map area and includes overlap areas with figure 4. Whitetail Creek flows in a north-northeast direction from the figure 8 west edge (south half) to the figure 4 north edge (west half) and joins Badger Creek north of the figure 8 map area near Piegan (see figure 4). Blacktail Creek flows in a northeast direction from the figure 8 south edge (west half) to the figure 8 northeast quadrant and then near the highway turns to flow in an east direction to the figure 8 east edge. East of the figure 8 map area Blacktail Creek turns to flow in a southeast direction to join northeast and north-northeast oriented Birch Creek, which is located south and east of the figure 8 map area. Four Horse Lake is located in an interesting valley with north-northeast oriented Jackson Coulee draining to Four Horse Lake and southeast-oriented Big Plum Coulee draining the Four Horse Lake basin to Blacktail Creek. Even though the Four Horse Lake basin drains in a southeast direction to Blacktail Creek a large through valley extends to the north and is drained at the north end by north-oriented Badger Creek tributaries seen in figure 4. This well-defined through valley provides evidence of what was once a south-oriented flood flow channel, which diverged at Four Horse Lake with one diverging channel located along the southeast-oriented Big Plum Coulee alignment while the other diverging channel was along the north-northeast oriented Jackson Coulee alignment. Note how the present day Jackson Coulee valley is linked by through valleys with the east-oriented Tail Feather Coulee valley (which drains to the Blacktail Creek valley) and also with the Blacktail Creek valley. The figure 8 map contour interval is 20 meters and the through valley just north of Four Horse Lake has a valley floor elevation at the drainage divide of between 1240 and 1260 meters while the hill to east rises to 1388 meters and the hill to the west rises to 1384 meters. This through valley is at least 120 meters deep. The through valley linking the Jackson Coulee valley with the Tail Feather Coulee valley elevation appears to be between 1220 and 1240 meters at the drainage divide (probably very close to 1240 meters) with elevations greater than 1400 meters being found on both sides. Headward erosion of the deep Blacktail Creek valley and its tributary Tail Feather Coulee valley captured the south-oriented flood flow on these diverging south-oriented flood flow channels. Subsequently headward erosion of the Badger Creek valley (north of the figure 8 map area) captured the south-oriented flood flow and flood waters on the north end of the beheaded flood flow channel reversed flow direction to erode the north-oriented Badger Creek tributary valleys north of Four Horse Lake and perhaps the north-oriented Jackson Coulee valley. For reasons not determinable from the figure 8 map evidence the resulting low gradient north-oriented valley became blocked forming Four Horse Lake with water overflowing in a southeast direction down the southeast-oriented flood flow channel to create the southeast-oriented Big Plum Coulee drainage.

Figure 9: Detailed map of Badger Creek-Four Horse Lake drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 9 illustrates the Badger Creek-Four Horse Lake drainage divide area seen in less detail in figure 8 above. Badger Creek flows in a north-northeast direction in the figure 9 northwest corner region. Four Horse Lake straddles the figure 9 south center edge and drains in a southeast direction to northeast-oriented Blacktail Creek (see figure 8). North-oriented drainage in section 6 flows to Badger Creek north of the figure 9 map area. Note how the small lakes in section 7 drain to Four Horse Lake and are not part of the north-oriented drainage system in the section 7 northeast corner and in section 6 to the north. The figure 9 map contour interval is 20 feet. The well-defined through valley in section 7 linking the north- and the south-oriented drainage routes has a valley floor elevation at the drainage divide of between 4140 and 4160 feet. Elevations in section 17 to the east rise to 4564 feet and elevations at the northwest corner of section 14 to the west rise to 4566 feet. The similarity of high elevations on both sides of the through valley suggests the possibility of a former erosion surface at that level and that a south-oriented flood flow channel at least 400 feet deep was eroded into that high level erosion surface on which the flood waters once flowed. The channel may have been eroded even deeper because it has become blocked in section 7 to form the lake basins. The blockage may be due to slumping or other types of earth movements, which partially filled what had first been a south-oriented valley and then was reversed to become a low gradient north-oriented valley when headward erosion of the deep Badger Creek valley beheaded the south-oriented flood flow. The through valley documents a major south-oriented flood flow channel that existed prior to headward erosion of the deep Badger Creek valley. At that time the 400-foot plus deep south-oriented flood flow channel had been eroded in a high level surface which was at least as high as the highest figure 9 elevations today. Flood waters could freely flow across that higher level surface toward the actively eroding Blacktail Creek valley to the south of figure 9. South-oriented flood flow eroded areas south of the present day Badger Creek-Blacktail Creek drainage divide while headward erosion of the deep Badger Creek valley and subsequent reversals of the beheaded south-oriented flood flow routes eroded regions north of the drainage divide so as to create the present day Badger Creek-Blacktail Creek drainage divide and the landscape seen today.

Figure 10: Badger Creek-Birch Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

 

Figure 10 illustrates the Badger Creek-Birch Creek drainage divide area south and east of the figure 6 map area and south and west of the figure 8 map area and includes overlap areas with both figures 6 and 8. Heart Butte (the town) is a small community located north of the figure 10 center. Birch Creek flows in a northeast direction across the figure 10 southeast quadrant. The South Fork Blacktail Creek originates in the figure 10 south center and flows in a northeast direction to join the east-oriented North Fork (unlabeled stream flowing from Green Lake) and to form northeast-oriented Blacktail Creek which flows to the figure 10 east edge (north half). Tail Feather Coulee originates south of Heart Butte and drains in an east direction to join Blacktail Creek in the figure 10 east half. The South Fork Whitetail Creek flows in a northeast direction along the south and southeast margins of Feather Woman Mountain and Heart Butte ( a mountain in figure 10 southwest quadrant) while the North Fork Whitetail Creek flows on the northwest and north margins of Feather Woman Mountain and Heart Butte (the mountain). The North and South Forks join just north and east of Heart Butte (the town) to form north-northeast oriented Whitetail Creek, which flows to the figure 10 north edge (east half). Badger Creek is labeled and flows in an east and northeast direction near the north edge of the figure 10 northwest quadrant. The figure 10 map area illustrates a region along the edge of the mountains and numerous northwest to southeast oriented through valleys cross the various drainage divides. Some of the through valleys are quite deep such as the through valley linking the North and South Forks Whitetail Creek found between Feather Woman Mountain and Heart Butte in the figure 10 southwest quadrant. The figure 10 contour interval is 20 meters and the through valley floor elevation at the drainage divide is between 1720 and 1740 meters. Feather Woman Mountain rises to 2316 meters while Heart Butte (the mountain) rises to 2092 meters which makes the through valley at least 350 meters deep. The through valley is a water eroded feature, although its orientation may be related to the underlying geologic structures. A shallower through valley can be seen north and east of Heart Butte also linking the North and South Forks Whitetail Creek. Study of the figure 10 map area reveals many other through valleys crossing each of the major drainage divides. The through valleys in the mountain regions suggest either flood waters once flowed across a high level erosion surface at least as high as the highest figure 10 elevations today or flood waters were flowing across the figure 10 map area as the mountains (and perhaps the entire region) were being uplifted. Probably some combination of these two hypotheses is correct, with deep erosion lowering the surface east of the mountains while uplift of the mountains to the west further increased the present day elevation differences.

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.