A geomorphic history based on topographic map evidence
Abstract:
The drainage divide between the Redwater River and Spearfish Creek in Wyoming and South Dakota is located at the north end of the Black Hills uplift area, USA. Although detailed topographic maps of the Redwater River-Spearfish Creek drainage divide area have been available for more than fifty years detailed map evidence has not previously been used to interpret the region’s geomorphic history. The interpretation provided here is based entirely on topographic map evidence. The Redwater River-Spearfish Creek drainage divide area is interpreted to have been eroded during immense southeast-oriented flood events, the first of which flowed on a topographic surface at least as high as the highest points in the present-day drainage divide area today, although the Black Hills area may have been uplifted during and/or following the flood. Flood flow across the Redwater River-Spearfish Creek drainage divide area ended when headward erosion of the deep northeast-oriented Belle Fourche River valley captured all southeast-oriented flood flow.
Introduction:
- The purpose of this essay is to use topographic map interpretation methods to explore Wyoming and South Dakota Redwater River-Spearfish Creek drainage divide area landform origins. Map interpretation methods can be used to unravel many geomorphic events leading up to formation of present-day drainage routes and development of other landform features. While each detailed topographic map feature provides detailed evidence to be explained, the solution must be consistent with explanations for adjacent area map evidence as well as solutions to big picture map evidence puzzles. I invite readers to improve upon my solutions or to propose alternate solutions that better explain evidence and are also consistent with adjacent map area and big picture evidence. Readers may do so either by making comments here or by writing and publishing their own essay.
- 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 essay 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 Redwater River-Spearfish Creek drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.
Redwater River-Spearfish Creek drainage divide area general location map
Figure 1: Redwater River-Spearfish Creek drainage divide area general 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 general location map for the Redwater River-Spearfish Creek drainage divide area. South Dakota is located east of the north-south state line and Wyoming is located to west. The Redwater River is the unlabeled northeast-oriented stream originating north of Sundance, Wyoming and flowing to Beulah, Wyoming and to the southeast-oriented Belle Fourche River near Belle Fourche, South Dakota. Spearfish Creek is the unlabeled north-oriented stream just east of the state line flowing through Spearfish, South Dakota to join the Redwater River between Spearfish and Belle Fourche, South Dakota. The Belle Fourche River originates in Wyoming and flows northeast and then north of the figure 1 map area where it turns abruptly southeast to flow southeast into the figure 1 north center and then turn east-northeast to join the northeast-oriented Cheyenne River in the figure 1 northeast quadrant. The Cheyenne River also originates in Wyoming and flows around the Black Hills south end before turning northeast to flow to the figure 1 northeast quadrant. The Black Hills are a domal uplift with an exposed core of Precambrian rocks and stand significantly higher than the surrounding plains region. This essay interprets the origin of Redwater River-Spearfish Creek drainage divide area erosional landforms in the context of an immense southeast oriented flood that flowed across the entire figure 1 map area and that was systematically captured by headward erosion of deep east- and northeast-oriented valleys, which diverted flood waters further and further northeast and north. The source of the southeast-oriented flood water cannot be determined from evidence presented here. However, based on the collective evidence illustrated and described in numerous Missouri River drainage basin landform origins research project essays (published on this website) flood waters can be traced headward to a North American ice sheet location and it can be demonstrated the floods occurred before or while the Black Hills area was being uplifted. Rapid melting of a thick North American ice sheet located in a deep “hole” would explain the flood water source and also why deep valleys eroded west and southwest to capture southeast-oriented flood waters and diverted flood waters further and further northeast and north into space in the deep “hole” the rapidly melting ice sheet once occupied. In addition, presence of a thick North American ice sheet in a deep “hole” north and east of the Black Hills might explain crustal warping that uplifted the Black Hills during an immense southeast-oriented flood. Uplift of the Black Hills may have been accelerated by crustal unloading as flood waters deeply eroded the region and removed overlying sedimentary layers.
Redwater River-Spearfish Creek drainage divide area detailed location map
Figure 2: Redwater River-Spearfish Creek drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 2 provides a detailed location map for the Redwater River-Spearfish Creek drainage divide area. Crook County is located in Wyoming and Lawrence County is located in South Dakota. The Redwater River originates in the Bear Lodge Mountains north of Sundance, Wyoming and flows northeast and southeast to Beulah, Wyoming before turning northeast to flow to Belle Fourche, South Dakota, where it joins the Belle Fourche River. Spearfish Creek originates in the limestone plateau area located south of Spearfish, South Dakota and flows north to join the Redwater River north of Spearfish. Between the north oriented Spearfish Creek and the northeast-oriented Redwater River are several north, northeast, and northwest oriented Redwater tributaries. Drainage divides between some of these Redwater River tributaries are investigated here, especially between northwest and northeast-oriented Cold Springs and Sand Creeks and Spearfish Creek. The Bear Lodge Mountains are separated from the main Black Hills uplift by the northeast-oriented Redwater River drainage basin, which has eroded a significant northeast-oriented valley. West of the Bear Lodge Mountains is the northeast-oriented Belle Fourche River (located in figure 2 northwest corner), which turns southeast north of the figure 2 map and flows to Belle Fourche Fourche, South Dakota, located along the figure 2 northeast quadrant north edge. Other Black Hills region drainage divide area essays can be found under Black Hills on the sidebar category list. Northwest-oriented drainage flowing to the figure 2 west center edge flows to the northeast-oriented Belle Fourche River. Southeast-oriented drainage in the Upton, Wyoming area (figure 2 southwest corner) flows to the southeast-oriented Cheyenne River south of the Black Hills and is addressed in the Wyoming’s Belle Fourche River-Cheyenne River drainage divide area essay. Drainage divide evidence north of the southeast-oriented Belle Fourche River is addressed by the Little Missouri River-Belle Fourche River drainage divide area north of Stoneville Flats essay and the Moreau River-Belle Fourche River drainage divide area essay (found under Moreau River).
Redwater River-Spearfish Creek drainage divide area south of Belle Fourche, South Dakota
Figure 3: Redwater River-Spearfish Creek drainage divide area south of Belle Fourche, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 3 illustrates the Redwater River-Spearfish Creek drainage divide area north end and also where the Redwater River joins the Belle Fourche River at Belle Fourche. The east-northeast-oriented Redwater River flows from the figure 3 southwest quadrant to join north-oriented Spearfish Creek near Jolly Dump (located midway between Belle Fourche and the figure 3 south edge) and then turns north to join the southeast-oriented Belle Fourche River (which makes a jog to the northeast at Belle Fourche). False Bottom Creek is the northwest-oriented Redwater River tributary flowing near Saint Onge in the figure 3 southeast corner to join the north-oriented Redwater River midway between Jolly Dump and Belle Fourche. False Bottom Creek originates in the Black Hills. Hay Creek is the east- and east-northeast oriented Belle Fourche River tributary located between the east-northeast oriented Redwater River valley segment and the southeast-oriented Belle Fourche River valley. Other essays present evidence suggesting the region north and northwest of figure 3 was eroded by southeast-oriented flood water. The southeast-oriented Belle Fourche River valley and northwest-southeast orientation of some figure 3 drainage routes and valleys supports that interpretation, although figure 3 has evidence suggesting significant north-oriented flood flow from the Black Hills uplift area (south of the figure 3 map area) moving north to the southeast-oriented Belle Fourche River valley. The north-oriented Redwater River valley has multiple northwest-oriented tributaries. These tributaries are evidence headward erosion of the north-oriented Redwater River valley beheaded what may have been southeast-oriented flow routes. If so, the flood water was diverted to the Belle Fourche River valley. Note the north-south through valley in the figure 3 west center linking the east-oriented Hay Creek valley with the east-northeast oriented Redwater River valley. This north-south through valley was eroded by water and at one time water flowed through it. Valleys such as this one provide evidence of anastomosing flood flow channels that were systematically dismembered as deeper valleys eroded headward to capture the flood flow.
Redwater River-Spearfish Creek drainage divide area west of Spearfish, South Dakota
Figure 4 illustrates the Redwater River-Spearfish Creek drainage divide area west of Spearfish and south of the figure 3 map area and includes overlap areas with figure 3. Spearfish Creek flows north-northeast from the figure 4 south edge to just south of Spearfish, where it turns slightly to flow north-northwest through Spearfish to the figure 4 north edge. Higgins Gulch is a major north-northeast oriented Spearfish Creek tributary flowing from the figure 4 south center to join Spearfish Creek north of Spearfish. Note north-oriented Beaver Creek, which flows to the Redwater River in the figure 4 north center. North-northeast-oriented Sand Creek joins the east-northeast oriented Redwater River at Beulah, Wyoming in the figure 4 northwest corner, however northwest-oriented Sand Creek is located in the southwest corner (unlabeled on figure 4). Elevations rise rapidly to the south. Lytle Hill in the figure 4 southwest corner is approximately 700 meters higher than the Redwater River valley at Beulah to the north. Spearfish Creek is the easternmost of several north-oriented Redwater River tributaries that have eroded valleys into the Black Hills north flank. A close look at these north-oriented tributaries reveals a history of stream captures, suggestive of an ever-changing anastomosing channel complex. For example, just south of Crow Peak in the figure 4 center is a through valley linking north-northwest oriented Crow Creek headwaters with northeast-oriented Higgins Gulch. A short distance upstream Higgins Gulch is a northwest-oriented valley and south of Citadel Rock there is a northwest-southeast oriented through valley linking the northwest-oriented Higgins Gulch valley segment with northeast-oriented Robison Gulch and also with southeast-oriented Eleven Hour Gulch (which flows to northeast-oriented Spearfish Creek south of the figure 4 map area). Other examples of through valleys are found in the figure 4 southwest corner where the northwest-oriented Sand Creek valley has beheaded the West and East Forks of northwest-oriented Dugout Gulch and north and south of Lytle Hill there are through valleys linking Shepherd Gulch with Bear Gulch. This and similar evidence strongly suggests what is today the steep Black Hills north slope was eroded by a north-oriented and ever-changing anastomosing channel complex. Where did the water come from? And, was this a steep north facing slope when much of the erosion took place?
Grand Canyon-Spearfish Canyon drainage divide area
Figure 5: Grand Canyon-Spearfish Canyon drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 5 illustrates the region south of the figure 4 map area and includes overlap areas with figure 4. Elevations in figure 5 southeast quadrant are more than 800 meters higher than elevations in the Redwater River valley near Beulah, Wyoming. Spearfish Creek flows northwest in the figure 5 southeast quadrant and then northeast to reach the figure 5 east edge (north center). Sand Creek flows northwest from south of Welcome (figure 5 center) to join north-northeast-oriented Cold Springs Creek near the figure 5 north edge (northwest corner area). Cold Springs Creek flows north and north-northeast through what is labeled as the Grand Canyon along the figure 5 west edge. Cold Springs Creek tributaries from the east are almost always northwest-oriented. This evidence suggests the deep north-oriented Cold Springs Creek valley eroded headward across multiple southeast-oriented flood flow routes or channels, such as might be found in a southeast-oriented anastomosing channel complex. The northwest-oriented tributary valleys were eroded by reversals of flood flow on the northwest ends of beheaded southeast-oriented flood flow routes. The reversed flood water flowed to the newly eroded and much deeper Cold Springs Creek valley. Often reversed flow channels captured southeast-oriented flood water from yet to be beheaded flood flow routes further south. For example, reversed flow on the Sand Creek valley route captured yet to be beheaded (by Cold Springs Creek valley headward erosion) southeast-oriented flood flow moving on the Idol Gulch alignment, and the captured flood waters eroded through valleys linking Idol Gulch headwaters with Sand Creek headwaters in the Welcome area. East of the Cold Springs Creek drainage basin one of the remarkable landscape features is the large number of through valleys. For example, headwaters of north-oriented Higgins Gulch are linked by multiple through valleys with south-oriented tributaries to east-southeast-oriented Iron Creek (flowing to northeast-oriented Spearfish Creek). Iron Creek is also linked by a through valley east of Beaver Crossing (figure 5 center east) with north-oriented Beaver Creek. The deep Iron Creek valley eroded west from a newly eroded and deep northeast-oriented Spearfish Creek valley to capture flood waters flowing southeast along what is today the northwest-oriented Sand Creek valley alignment and those captured flood waters eroded the through valleys linking Sand Creek headwaters areas with the present day Beaver Creek valley and with the Iron Creek valley. Further south, Beaver Creek headwaters are linked by a through valley with southeast-oriented Schoolhouse Creek, which flows to northeast-oriented Little Spearfish Creek (which flows to the northeast-oriented Spearfish Creek). In other words, southeast-oriented flood water once flowed across the Cold Springs Creek-Spearfish Creek drainage divide and was captured by headward erosion of the deep Spearfish Creek valley or canyon. Flood water moving to Spearfish Creek was then systematically captured by headward erosion of other north-oriented valleys (e.g. Higgins Gulch, the Beaver Creek valley, Shepherd Gulch, and Cold Springs Creek valley in that order). Headward erosion of the deep Cold Springs Creek valley captured all flood flow moving across the figure 5 map area.
Detailed map of through valley linking Beaver Creek and Spearfish Creek
Figure 6 provides a detailed map of the Deer Creek-Iron Creek through valley linking Beaver Creek and Spearfish Creek and also of through valleys linking Higgins Gulch with Spearfish Creek. These through valleys were illustrated in less detail in figure 5 above. Refer back to previous figures to see where Spearfish Creek, Higgins Gulch, and Beaver Creek flow. Evidence provided by these through valleys suggest the northeast-oriented Spearfish Creek valley captured southeast-oriented flood flow moving on what are now the north-oriented Higgins Gulch and Beaver Creek valley routes. That captured flood flow eroded multiple southeast-oriented valleys headward from what is now the east-oriented Iron Creek valley. The multiple southeast-oriented valleys suggest the presence of a southeast-oriented anastomosing channel complex that was being captured by headward erosion of the deep northeast-oriented Spearfish Creek valley. South-oriented flood flow on the Higgins Gulch valley routes was beheaded and reversed first, causing flow in Higgins Gulch to flow north instead of south and also creating the Higgins Gulch-Iron Creek drainage divide. Subsequently south-oriented flood flow on the Beaver Creek valley route was beheaded and reversed, causing waters in the Beaver Creek valley to flow north and also to create the Beaver Creek-Spearfish Creek drainage divide. The multiple through valleys here suggest an ever-changing southeast-oriented anastomosing channel complex was being captured by an ever-changing north-oriented anastomosing channel complex. Further, the evidence suggests captures were taking place in sequence from east to west, suggesting they may have been related to headward erosion of the deep Belle Fourche River valley and its tributary Redwater River valley to the north. Quite possibly simultaneous uplift of the Black Hills region contributed to the captures and flow reversals.
Cold Springs Creek-Spearfish Creek drainage divide area
Figure 7: Cold Springs Creek-Spearfish Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 7 illustrates the Cold Springs Creek-Spearfish Creek drainage divide area south of the figure 5 map area and includes a very thin overlap area with figure 5. North-northwest oriented Cold Springs Creek flows from the figure 7 south edge (center west) to the figure 7 north edge (northwest corner). Deer Creek is a northwest-oriented Cold Springs Creek tributary joining Cold Springs Creek near Moskee (figure 7 northwest corner). Adams Gulch, Lost Canyon, and Stanton Draw are additional northwest-oriented Cold Springs Creek tributaries and they are linked by through valleys with northwest-oriented valleys further east. The northwest-oriented Grand Canyon valley extends from the Hardy Guard Station (figure 7 south center) to the figure 7 north edge (northwest quadrant). East of the Grand Canyon is northwest-oriented Riflepit Canyon, which flows to the figure 7 north edge (center). Further east is north-oriented Little Spearfish Creek and northeast-oriented Spearfish Creek flows from near the Hardy Guard Station along the highway to the figure 7 northeast corner area. Several through valleys link the northwest-oriented Riflepit Canyon with the north-oriented Little Spearfish Creek valley. A maze of through valleys in the Hardy Guard Station area (better seen on more detailed topographic maps) link northwest-oriented Grand Canyon headwaters with northeast-oriented Spearfish Creek headwaters and also link northwest-oriented Riflepit Canyon headwaters with north-oriented Little Spearfish Creek headwaters. Further, the through valleys link northwest-oriented Grand Canyon headwaters with northwest-oriented Riflepit Canyon headwaters. These through valleys were eroded by southeast-oriented flood flow that moved southeast along the Riflepit Canyon valley alignment to what was then the actively eroding north-oriented Little Spearfish Creek valley head and southeast along the Grand Canyon valley alignment to what was then the actively eroding northeast-oriented Spearfish Creek valley head. Flood flow was systematically beheaded and reversed by headward erosion of the deep Cold Springs Creek valley, with flood flow on the Riflepit Canyon valley alignment being reversed first. Reversed flood flow on the Riflepit Canyon valley alignment captured yet to be beheaded southeast-oriented flood flow from the Grand Canyon valley alignment and reversed flood flow on the Grand Canyon alignment captured yet to be beheaded flood flow moving on the Lost Canyon alignment. The maze of through valley is evidence the situation was much more complicated than I have described, however the landscape was being eroded by an ever-changing complex of southeast-oriented anastomosing channels that was being captured by headward erosion of what must have been an ever-changing complex of north-oriented anastomosing channels.
Redwater River-Cheyenne River (Cold Springs Creek-Castle Creek) drainage divide area
Figure 8: Redwater River-Cheyenne River (Cold Springs Creek-Castle Creek) drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 8 illustrates the region south of the figure 7 map area and includes overlap areas with figure 7. Lawrence and Pennington Counties are in South Dakota. Crook and Weston Counties are in Wyoming. Northwest-oriented Cold Springs Creek headwaters are located in the Pennington County northwest corner. Readers may want to refer back to figure 1 to better understand the remarkable drainage divide located here in figure 8. Cold Springs Creek as described previously flows to Sand Creek, which flows to the Redwater River and then to the southeast-oriented Belle Fourche River north of the Black Hills. Southeast-oriented Castle Creek flows to the figure 8 southeast corner. Castle Creek flows southeast, but eventually turns northeast to join east-oriented Rapid Creek and flow to the northeast-oriented Cheyenne River east of the Black Hills. In the figure 8 south center Stockade Beaver Creek first flows northwest and then south to southeast-oriented Beaver Creek, which flows to the southeast-oriented Cheyenne River south of the Black Hills. Northwest-oriented Soldier Creek (labeled Creek on figure 8) originates at State Line Springs south of Buckhorn, Wyoming and flows to the figure 8 west edge (center north) and flows northwest to west-oriented Inyan Kara Creek, which eventually reaches the northeast-oriented Belle Fourche River west of the Black Hills. A maze of through valleys links these four drainage routes and provides evidence flood water once flowed southeast across this drainage divide area to what is now the Castle Creek drainage basin and those flood waters were captured by Rapid Creek valley headward erosion, which was eroding headward from what was then the deep and actively eroding northeast-oriented Cheyenne River valley (Rapid Creek is not shown in this essay). Subsequently flood waters were captured by Stockade Beaver Creek valley headward erosion, which was eroding headward from what was then the deep and actively eroding southeast-oriented Cheyenne River valley (which had eroded around the Black Hills south end). Next flood flow was reversed in the Cold Springs Creek valley by headward erosion of what was then the deep and actively eroding southeast-oriented Belle Fourche River valley and finally flood flow was reversed on the Inyan Kara Creek-Soldier Creek alignment by headward erosion of what was then the actively eroding northeast-oriented Belle Fourche River valley.
Detailed map of through valley linking Cold Spring Creek and Castle Creek
Figure 9: Detailed map of through valley linking Cold Spring Creek and Castle Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 9 illustrates a detailed map of the through valley linking Cold Spring Creek with Castle Creek illustrated in less detail in figure 8 above. One northwest-oriented branch of Cold Springs Creek originates near the Michelson Ranch in the figure 9 northwest quadrant and the other northwest branch originates near the McCoy Ranch just to the west. As previously described Cold Springs Creek flows northwest and north to the Redwater River and then to the southeast-oriented Belle Fourche River north of the Black Hills. Headwaters of southeast-oriented Castle Creek are located near the Dolan Ranch (figure 9 center) and flow south before turning east-southeast to flow along the figure 9 south center edge. The multiple through valleys across the Cold Spring Creek-Castle Creek drainage divide suggests the valleys were eroded by a southeast-oriented anastomosing channel complex, with these valleys perhaps being the final southeast-oriented flow routes before flood flow in what is today the northwest-oriented Cold Springs Creek headwaters valleys was reversed to flow northwest (and to create the present day Cold Springs Creek-Castle Creek drainage divide).
Detailed map of through valley linking Cold Spring Creek and Stockade Beaver Creek
Figure 10: Detailed map of through valley linking Cold Spring Creek and Stockade Beaver Creek. United States Geological Survey map digitally presented using National Geographic Society TOPO software.
Figure 10 illustrates a detailed map of the area southwest of figure 9 and includes significant overlap areas with figure 9. Figure 10 illustrates the through valley linking northwest-oriented Cold Springs Creek headwaters with northwest and south-oriented Stockade Beaver Creek headwaters, which was illustrated in less detail in figure 8. Southeast-oriented Castle Creek flows to the figure 10 southeast corner. The southern northwest-oriented Cold Springs Creek headwaters branch flows to figure 10 north center edge. As previously described, northwest-oriented Cold Springs Creek flows to the Redwater River and then to the southeast-oriented Belle Fourche River located north of the Black Hills. Northwest-oriented Dry Beaver Creek flows from the figure 10 south center to become south-oriented Stockade Beaver Creek. Stockade Beaver Creek as previously described flows to southeast-oriented Beaver Creek and then to the southeast-oriented Cheyenne River located south of the Black Hills. Note how a deep north-south through valley links northwest-oriented Dry Beaver Creek with northwest-oriented Cold Springs Creek. That through valley extends south of the figure 10 map area and links northwest-oriented Beaver Creek (which flows to south-oriented Stockade Beaver Creek). The through valley also provides evidence flood water once flowed south from what is now the Cold Springs Creek drainage basin to the Cheyenne River south of the Black Hills. Headward erosion of that valley beheaded southeast-oriented flood flow to the southeast-oriented Castle Creek valley and reversed flow in what are today the two northwest-oriented Cold Springs Creek headwaters branch valleys. Other through valleys link Castle Creek headwaters with the north-south through valley and provide additional support the anastomosing channel complex interpretation. Soldier Spring along the figure 10 west center edge is the headwaters of northwest-oriented Soldier Creek, which flows to west-oriented Inyan Kara Creek, which in turn flows to the northeast-oriented Belle Fourche River located west of the Black Hills.
Additional information and sources of maps studied
This essay has provided only a sample of the detailed topographic map evidence supporting the flood erosion interpretation. Many additional illustrations could be provided. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of available data. Maps used in this study were created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.
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