A geomorphic history based on topographic map evidence

The Rosebud Creek-Tongue River drainage divide area is located in Montana, USA. Although detailed topographic maps of the Rosebud Creek-Tongue River drainage divide area have been available for more than fifty years detailed map evidence has not previously been used to interpret the region’s geomorphic history. The interpretation provided here is based entirely on topographic map evidence. The Rosebud Creek-Tongue River drainage divide area is interpreted to have been eroded during immense southeast-oriented flood events, the first of which flowed on a topographic surface at least as high as the highest points in the present-day drainage divide area. Flood erosion across the drainage divide ended when headward erosion of the deep Yellowstone River valley captured all southeast-oriented flood flow.

Introduction:

• The purpose of this essay is to use topographic map interpretation methods to explore Montana Rosebud Creek-Tongue River drainage divide area landform origins. Map interpretation methods can be used to unravel many geomorphic events leading up to formation of present-day drainage routes and development of other landform features. While each detailed topographic map feature provides detailed evidence to be explained, the solution must be consistent with explanations for adjacent area map evidence as well as solutions to big picture map evidence puzzles. I invite readers to improve upon my solutions or to propose alternate solutions that better explain evidence and are also consistent with adjacent map area and big picture evidence. Readers may do so either by making comments here or by writing and publishing their own essays and then by leaving a link to those essays in a comment here.

• This essay is also exploring a paradigm in which erosional landforms are interpreted as evidence left by immense glacial melt water floods. Implied in that interpretation is the immense floods were derived from a thick North American ice sheet that created a deep “hole” in the North American continent and also melted fast. The previously unexplored paradigm being tested in this and similar essays is a thick North American ice sheet, comparable in thickness to the present day Antarctic ice sheet, occupied approximately the North American region usually recognized to have been glaciated and through its weight and erosive actions created a “deep” North American “hole”, through its weight and deep erosion (and perhaps deposition) along major south-oriented melt water flow routes caused significant crustal warping and tectonic change, through its action of melting fast produced immense floods that flowed across the continent, and through its action of melting fast systematically opened up space in the ice sheet created “hole” so headward erosion of newly developed north-oriented drainage systems captured immense south-oriented melt water floods and diverted immense melt water floods north into space the ice sheet had once occupied.

• If this previously unexplored paradigm is correct the geographic region explored by this essay should contain evidence of immense floods that were captured by headward erosion of new valley systems so as to cause the floods to flow in a different direction. Ability of this previously unexplored paradigm to explain Rosebud Creek-Tongue River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Rosebud Creek-Tongue River drainage divide area location map

Figure 1: Rosebud Creek-Tongue 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 provides a Rosebud Creek-Tongue River drainage divide area location map and illustrates a region in eastern Montana, which is located north of the west to east green border line. The state of Wyoming is located south of Montana. The Yellowstone River flows from Billings in a northeast direction to Fallon, located near the figure 1 northeast corner. The Tongue River flows northeast from near Sheridan, Wyoming into Montana and then turns northwest to join the northeast-oriented Yellowstone River at Miles City, Montana. Rosebud Creek originates in the Wolf Mountains area of Montana (just north of the Wyoming state line) and flows north, northeast, and northwest to join the Yellowstone River at Rosebud, Montana. Figure 1 illustrates southeast and northwest-oriented Yellowstone River tributaries. The southeast and northwest-orientation of tributary valleys is evidence the northeast-oriented Yellowstone River valley eroded southwest across multiple southeast-oriented flood flow routes, such as might be found in a large-scale flood-formed anastomosing channel complex. Northwest-oriented tributary valleys were eroded by reversed flood flow on northwest ends of beheaded flood flow channels. Because channels were anastomosing (meaning they were interconnected) reversed flood flow on beheaded flood flow channels often captured yet to be beheaded southeast-oriented flood flow from flood flow channels further to the southwest. Such captures of yet to be beheaded flood flow often helped erode significant northwest-oriented tributary valleys. Based on the northwest-southeast orientation of Yellowstone River tributary streams, landform evidence illustrated in this essay is interpreted in the context of an immense southeast-oriented flood flowing across the entire figure 1 map area and which was systematically captured and diverted further and further to the northeast by headward erosion of deep valleys eroded into a topographic surface at least as high as the figure 1 region highest elevations today. In the figure 1 map region headward erosion of the northeast-oriented Tongue River valley first captured the southeast-oriented flood flow and diverted the flood waters more directly to the northeast-oriented Yellowstone River valley (downstream from Miles City, Montana) and second headward erosion of the Rosebud Creek valley captured many southeast-oriented flood flow routes moving water to the newly eroded Tongue River valley.  Detailed maps below provide evidence supporting this interpretation. The Big Dry Creek-Yellowstone River drainage divide area essay, the Musselshell River-Yellowstone River drainage divide area essay, and the Yellowstone River-Tongue River drainage divide area essay  describe drainage divide areas located northwest and north of the Rosebud Creek-Tongue River drainage divide area discussed here and can be found under Yellowstone River on the sidebar category list. The Tongue River-Otter Creek drainage divide area essay and in the Tongue River-Pumpkin Creek drainage divide area essay describe drainage divide areas located east of the area discussed here and can be found under Tongue River on the sidebar category list.

Rosebud Creek-Tongue River drainage divide area detailed location map

Figure 2: Rosebud Creek-Tongue River drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 illustrates a somewhat more detailed map of the Rosebud Creek-Tongue River drainage divide area discussed here. Big Horn and Powder River Counties are located in Montana and Rosebud County is located between them. The Rosebud Creek-Tongue River drainage divide area discussed here is located in Big Horn County and Rosebud County. The Tongue River flows northeast from the figure 2 south center edge to Ashland and Brandenberg, Montana before flowing to the figure 2 northeast corner. Rosebud Creek flows north from the Wolf Mountains area in the figure 2 southwest quadrant and then turns northeast near Bushby to flow into Rosebud County where it turns to flow north and northwest. Figure 2 shows numerous southeast-oriented and northwest-oriented Tongue River tributaries and also many southeast-oriented and northwest-oriented Rosebud Creek tributaries. This northwest-southeast drainage alignment is evidence the northeast-oriented Tongue River valley eroded southwest to capture the southeast-oriented flood flow. The southeast-oriented tributary valleys were eroded by southeast-oriented flood flow moving into the newly eroded and deep Tongue River valley and the northwest-oriented tributary valleys were eroded by reversals of flood flow on the northwest ends of beheaded southeast-oriented flood flow routes. Subsequently the Rosebud Creek valley eroded south, southwest, and south across the same southeast-oriented flood flow routes to capture flood waters that were moving to the newly eroded Tongue River valley. Because flood waters move in and erode anastomosing (or interconnected) channels reversed flood flow on a beheaded flood flow route could capture flood flow from yet to be beheaded flood flow routes. Such captures of yet to be beheaded flood flow could enable the reversed flood flow routes to erode much deeper and larger northwest-oriented valleys than might otherwise be possible. Often evidence for such flow reversals and captures can be found on detailed topographic maps. Detailed maps below start north of Brandenberg and progress south along the Rosebud Creek-Tongue River drainage divide and conclude with a look at the South Fork Rosebud Creek-Tongue River drainage divide area just north of the Montana-Wyoming state line.

Eagle Creek-Ranch Creek drainage divide area

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

Figure 3 illustrates the Eagle Creek-Ranch Creek drainage divide area at the north end of the Rosebud Creek-Tongue River drainage divide area discussed here. Areas north and east of the figure 3 map are illustrated and discussed in a Yellowstone River-Tongue River drainage divide essay. The northeast-oriented Tongue River is located in the figure 3 southeast corner. North-northwest oriented Rosebud Creek is located in the figure 3 southwest corner. Eagle Creek flows northwest from the figure 3 center area and then west in the figure 3 northwest quadrant and joins Rosebud Creek west of the figure 3 map area. South of Eagle Creek other Rosebud Creek tributaries shown are either northwest oriented or have northwest oriented valley segments. Tongue River tributaries are almost all southeast-oriented. Ranch Creek originates in the figure 3 center area (southeast of where Eagle Creek originates) and flows southeast to join the Tongue River near the figure 3 southeast corner. Shallow through valleys link northwest oriented Eagle Creek headwaters with  southeast-oriented Ranch Creek headwaters. Similar through valleys can be seen linking other northwest-oriented Rosebud Creek tributary headwaters with other southeast-oriented Tongue River tributary headwaters. These multiple through valleys eroded across what is today a major drainage divide provide evidence that multiple southeast-oriented flood flow channels once crossed the present day drainage divide flowing on a topographic surface at least as high as the highest points on the drainage divide today. The multiple southeast-oriented channels suggest flood waters eroded a southeast-oriented anastomosing channel complex. Based on these through valleys and the tributary orientations figure 3 evidence further suggests the deep northeast-oriented Tongue River valley eroded southwest to capture the southeast-oriented flood flow and to divert the flood waters northeast and north to what probably was then the actively eroding deep northeast-oriented Yellowstone River valley. Subsequently the deep north-northwest oriented Rosebud Creek valley eroded south to capture the southeast-oriented flood flow and to divert the flood waters north to what probably was then the actively eroding Yellowstone River valley. Reversals of flood flow on the northwest ends of the beheaded southeast-oriented flood flow routes eroded the northwest- and west-oriented Rosebud Creek tributary valleys and created the Rosebud Creek-Tongue River drainage divide.

Rosebud Creek-Tongue River drainage divide area near Gobblers Knob

Figure 4: Rosebud Creek-Tongue River drainage divide area near Gobblers Knob. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Rosebud Creek-Tongue River drainage divide area south of the figure 3 map area and includes overlap areas with figure 3. Rosebud Creek flows north along the figure 4 west edge. The northeast-oriented Tongue River is located in the figure 4 east half. West-northwest oriented Cherry Creek is the Rosebud Creek tributary in the figure 4 northwest corner area. Most other Rosebud Creek tributaries are northwest oriented, although John Hen Creek has northwest oriented headwaters and then turns southwest to flow to north-oriented Rosebud Creek as a barbed tributary. Tongue River tributaries shown from the northwest are southeast-oriented and from the southeast are northwest oriented. Figure 4 evidence is similar to the figure 3 evidence. Multiple shallow through valleys cross the present day Rosebud Creek-Tongue River drainage divide and link northwest-oriented Rosebud Creek headwaters with southeast-oriented Tongue River headwaters. The through valleys and the tributary orientations provide evidence that southeast-oriented flood flow once moved in multiple channels across the present day Rosebud Creek-Tongue River drainage divide. The flood waters were flowing on a topographic surface at least as high as the highest figure elevations today, which means the deep north-oriented Rosebud Creek valley did not exist. Flood waters were captured by headward erosion of the deep northeast-oriented Tongue River valley, which diverted the flood water northeast and north to what probably was then the actively eroding Yellowstone River valley. Subsequently headward erosion of the deep north-oriented Rosebud Creek valley captured the flood flow and diverted flood waters to what at that time was the probably the actively eroding Yellowstone River valley. Headward erosion of the Rosebud Creek valley beheaded southeast-oriented flood flow routes to the newly eroded Tongue River valley and flood waters on the northwest ends of beheaded flood flow routes reversed flow direction to flow northwest and west to the newly eroded Rosebud Creek valley. Reversal of flood flow also eroded the northwest- and west-oriented Rosebud Creek tributary valleys and created the present day Rosebud Creek-Tongue River drainage divide.

Rosebud Creek-Tongue River drainage divide area west of Brandenberg

Figure 5: Rosebud Creek-Tongue River drainage divide area west of Brandenberg. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Rosebud Creek-Tongue River drainage divide area west of Brandenberg and is located south of the figure 4 map area and includes overlap areas with figure 4. The north-northeast oriented Tongue River is located in the figure 5 east half and flows from the figure 5 south edge to the figure 5 northeast corner. Rosebud Creek is located in the figure 5 west half and flows northeast from the figure 5 west edge and then turns north to flow to the figure 5 north edge. Tongue River tributaries from the west are southeast oriented and from the east are northwest oriented. Rosebud Creek tributaries from east are northwest oriented and from the west are generally southeast-oriented, although there are some exceptions. Again multiple shallow through valleys link headwaters of southeast-oriented Tongue River tributaries with headwaters of northwest-oriented Rosebud Creek tributaries. The through valleys along with the tributary orientations provide evidence that multiple channels of southeast-oriented flood flow once moved across the figure 5 map area on a topographic at least as high as the present day Rosebud Creek-Tongue River drainage divide highest elevations. The deep north-northeast oriented Tongue River valley eroded headward into that high level topographic surface to capture southeast-oriented flood flow and to divert flood water north to what was then the newly eroded and northeast-oriented Yellowstone River valley. Southeast-oriented Tongue River tributary valleys were eroded headward into the newly eroded Tongue River valley west valley wall. Headward erosion of the north- and northeast-oriented Rosebud Creek next captured the southeast-oriented flood flow and diverted flood waters north to the newly eroded Yellowstone River valley, which by that time had eroded further to the southwest. Flood waters on northwest ends of beheaded southeast-oriented flood flow routes reversed flow direction to flow northwest into the newly eroded Rosebud Creek valley. Reversal of flood flow eroded northwest-oriented Rosebud Creek tributary valleys and created the Rosebud Creek-Tongue River drainage divide.

Rosebud Creek-Greenleaf Creek-Tongue River drainage divide area

Figure 6: Rosebud Creek-Greenleaf Creek-Tongue River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Rosebud Creek-Greenleaf Creek drainage divide area and the Greenleaf Creek-Tongue River drainage divide area south and west of the figure 5 map area and includes overlap areas with figure 5. Northeast-oriented Rosebud Creek is located in the figure 6 northwest corner. Greenleaf Creek flows north-northeast from the figure 6 south center and then northeast and north to the figure 6 northeast quadrant. North of figure 6 (seen in figure 5) Greenleaf Creek turns northwest to flow to northeast-oriented Rosebud Creek. The north-oriented Tongue River is located just east of the figure 6 map area and east oriented streams flowing to the figure 6 east edge are Tongue River tributaries. Tributary orientations in figure 6 are much more diverse than in previous figures (and also in following figures), perhaps because in the figure 6 southwest quadrant and south center there are uplands that appear to be capped by some type of resistant rock. However, Greenleaf Creek headwaters which originate in the figure 6 south center upland region begin with a short southeast-oriented valley segment and then after turning northeast have northwest-oriented tributaries. The northwest-oriented Greenleaf Creek tributaries are linked by shallow through valleys eroded across an upland ridge with southeast-oriented headwaters of Tongue River tributaries. Further north northeast-oriented Greenleaf Creek is linked by east and southeast-oriented through valleys with east-oriented Lay Creek, which flows to the north-oriented Tongue River. West of Greenleaf Creek north-oriented Bean Creek (flowing to the figure 6 north edge) has northwest-oriented headwaters linked by shallow through valleys with the northeast-oriented Greenleaf Creek valley. The above mentioned evidence and similar evidence found throughout the figure 6 map area and adjacent regions supports the interpretation that southeast-oriented flood waters once flowed on a topographic surface at least as high as the highest figure 6 elevations today. The north-oriented Tongue River valley eroded south to capture the southeast-oriented flood flow and divert flood waters north and northeast. Subsequently the Rosebud Creek-Greenleaf Creek valley eroded south to capture the southeast-oriented flood waters and divert the flood flow north to a more western Yellowstone River valley location. Still later the northeast-oriented Rosebud Creek valley eroded headward to capture the flood waters and move the flood flow more directly to the north-oriented Rosebud Creek valley. I have left out many details involving tributary valleys, but those details can all be worked out in the context of the bigger picture history provided.

Rosebud Creek-Tongue River drainage divide area near Lame Deer

Figure 7: Rosebud Creek-Tongue River drainage divide area near Lame Deer. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Rosebud Creek-Tongue River drainage divide area south of the figure 6 map area and includes overlap areas with figure 6. Figure 7 has been reduced so as to include both Rosebud Creek and the Tongue River. Northeast-oriented Rosebud Creek is located in the figure 7 northwest corner and the northeast-oriented Tongue River is located in the figure 7 southeast corner. Lame Deer Creek is the northwest-oriented Rosebud Creek tributary flowing through Lame Deer, Montana to join Rosebud Creek in the figure 7 northwest corner. Figure 7 tributaries to northeast-oriented Rosebud Creek are generally northwest oriented, although Lame Deer Creek has northeast-oriented and southwest-oriented tributaries, suggesting reversed flood flow on the Lame Deer Creek alignment captured significant flood flow that had been moving in adjacent channels. Tongue River tributaries, except in the figure 7 northeast corner, are generally southeast oriented. The southeast and then northeast-oriented Greenleaf Creek headwaters are located at the northwest corner of the figure 7 northeast quadrant, with northwest-oriented Ash Creek flowing to northeast-oriented Greenleaf Creek along the figure 7 north edge. While probably difficult to see on this reduced map there are shallow through valleys linking headwaters of northwest-oriented Rosebud Creek tributaries with headwaters of southeast-oriented Tongue River tributaries. The tributary orientations and the shallow through valleys again provide evidence that southeast-oriented flood waters once flowed across the figure 7 map area on a topographic surface at least as high as the highest figure 7 elevations today. Headward erosion of the northeast-oriented Tongue River captured the southeast-oriented flood flow and diverted the flood water northeast and north to the Yellowstone River valley. Subsequently headward erosion of the Rosebud Creek valley captured the flood waters and diverted the flood water northeast and north to a more western Yellowstone River valley location. Flood waters on the northwest ends of beheaded flood flow routes reversed flow direction to flow northwest to the newly eroded Rosebud Creek valley and by doing so eroded northwest-oriented Rosebud Creek tributary valleys and created the Rosebud Creek-Tongue River drainage divide.

Rosebud Creek-Muddy Creek-Tongue River drainage divide area

Figure 8: Rosebud Creek-Muddy Creek-Tongue River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 illustrates the Rosebud Creek-Muddy Creek drainage divide area and the Muddy Creek-Tongue River drainage divide area south and west of the figure 7 map area. The figure 7 southwest corner coincides with the figure 8 northeast corner and there is a small overlap area. North-oriented Rosebud Creek is located along the figure 8 west edge. The northeast-oriented Tongue River is located southeast of the figure 8 map area. The East and West Forks of Muddy Creek originate in the figure 8 center area north of Muddy Lake and flow parallel and adjacent to each other in northeast direction until West Fork Muddy Creek turns northwest at Big Bend, and after flowing northwest turns north to flow to the figure 8 north edge. The East Fork Muddy Creek continues to flow northeast toward the figure 8 northeast corner where it turns northwest, and north of figure 8 the East and West Forks of Muddy Creek join and flow north to join northeast-oriented Rosebud Creek. Note how Rosebud Creek tributaries from the east are northwest-oriented or have northwest-oriented tributaries and/or headwaters. Also note how Tongue River tributaries are southeast-oriented. The West Fork of Muddy Creek has a northwest-oriented valley segment, which suggests that valley segment was eroded by reversed flood flow. Also note northwest-oriented headwaters and tributaries to northeast-oriented tributaries to the northwest-oriented West Fork valley. In the figure 8 northeast corner tributaries to the East Fork of Muddy Creek are northwest oriented and there are northwest-oriented valleys draining to the East Fork further to the southwest. Multiple shallow through valleys cross all major drainage divides and provide evidence the figure 8 map area was eroded by southeast-oriented flood water that originally flowed on a topographic surface at least as high as the present day highest figure 8 elevations. Following headward erosion of the Tongue River valley the East Fork Muddy Creek valley eroded headward into the region to capture southeast-oriented flood flow to the newly eroded Tongue River valley. The West Fork Muddy Creek valley then eroded headward to capture the southeast-oriented flood flow. Finally the north-oriented Rosebud Creek valley eroded south to capture  flood flow moving to the West Fork Muddy Creek valley and to the Tongue River valley (south of the West Fork of Muddy Creek).

Rosebud Creek-Tongue River drainage divide in Canyon Creek area

Figure 9: Rosebud Creek-Tongue River drainage divide in Canyon Creek area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Rosebud Creek-Tongue River drainage divide area south of the figure 8 map area (there is a small gap between figure 8 and 9). The northeast-oriented Tongue River is located in the figure 9 southeast corner. Rosebud Creek flows east and then northwest in the southwest corner. West of figure 9 Rosebud Creek turns north and flows north just west of the figure 9 west edge. Figure 9 Rosebud Creek tributaries are almost all northwest-oriented and Tongue River tributaries are almost all southeast-oriented. The North and South Forks of Canyon Creek flow southeast from the Taylor Desert area and join to form southeast-oriented Canyon Creek, which joins the northeast-oriented Tongue River near the figure 9 east edge. Multiple shallow through valleys eroded into the Rosebud Creek-Tongue River drainage divide link headwaters of northwest-oriented Rosebud Creek tributaries with headwaters of southeast-oriented Tongue River tributaries. The through valleys and the tributary orientations again provide evidence that southeast-oriented flood water once flowed across the figure 9 map area on a topographic surface at least as high as the highest figure 9 elevations today. Flood waters were captured by headward erosion of the deep northeast-oriented Tongue River valley and diverted northeast and north to the Yellowstone River valley. Subsequently headward erosion of the deep Rosebud Creek valley captured the southeast-oriented flood flow and diverted the water north to a more western point on what was then the actively eroding northeast-oriented Yellowstone River valley. Flood waters on the northwest ends of beheaded flood flow routes reversed flow direction to flow northwest to the newly eroded north-oriented Rosebud Creek valley. The reversed flood flow eroded northwest-oriented Rosebud Creek tributary valleys and created the present day Rosebud Creek-Tongue River drainage divide.

South Rosebud Creek-Tongue River drainage divide area

Figure 10: South Rosebud Creek-Tongue River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 illustrates the South Fork Rosebud Creek-Tongue River drainage divide area. The figure 10 map area is located south and west of the figure 9 map area and there is a small gap between the figures. The east-northeast oriented South Fork Rosebud Creek is located in the figure 10 northwest corner. The flooded northeast-oriented Tongue River valley is located in the figure 10 southeast corner (the flooded valley is Tongue River Reservoir). Note how Tongue River tributaries are southeast-oriented and how some begin at a southeast-facing escarpment located just southeast of where the east-northeast oriented South Fork Rosebud Creek turns to flow north. Also note how through valleys link the South Fork Rosebud Creek valley with headwaters of southeast-oriented Tongue River tributaries. The southeast-facing escarpment is a large abandoned headcut that was being eroded headward by southeast-oriented flood flow moving into the newly eroded and deep northeast-oriented Tongue River valley. Flood flow that was eroding the southeast-facing escarpment to the northwest was beheaded by headward erosion of the South Fork Rosebud Creek valley. Headward erosion of the South Fork Rosebud Creek valley across the southeast-oriented flood flow routes diverted the flood waters to the north and cut off all flood flow to what had been the actively eroding southeast-facing headcut face. The South Fork Rosebud Creek originates just west of the figure 10 map area, indicating that flood flow to the South Fork Rosebud Creek was beheaded further west almost as soon as the South Fork Rosebud Creek valley had been eroded. While not visible in figure 10 a look at figure 1 shows headward erosion of the Little Bighorn River valley, which is located west of figure 10, was responsible for beheading southeast-oriented flood flow to the newly eroded South Fork Rosebud Creek valley.

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.