Cannonball River-Grand River drainage divide landform origins, Standing Rock Indian Reservation, North and South Dakota, USA

Authors

A geomorphic history based on topographic map evidence

Abstract:

The Standing Rock Indian Reservation Cannonball River-Grand River drainage divide area discussed here is located in along the South Dakota-North Dakota border, USA. Although detailed topographic maps of the Cannonball River-Grand 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 Cannonball River-Grand River east end 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 ended when headward erosion of the southeast-northeast-oriented Cannonball River valley captured all southeast-oriented flood flow.

Preface:

The following interpretation of detailed topographic map evidence is provided as evidence in the Missouri River drainage basin landform origins research project, which is compiling similar evidence for all major drainage divides contained within the Missouri River drainage basin and for all major drainage divides with and within certain adjacent drainage basins. The research project is interpreting evidence in the context of a previously unexplored geomorphology paradigm, which is briefly described in the introduction below. Project essays are listed on the sidebar category list under their appropriate Missouri River tributary drainage basin, Missouri River segment drainage basin (by state), and/or state in which the Missouri River drainage basin is located.

Introduction

  • The purpose of this essay is to use topographic map interpretation methods to explore Cannonball River-Grand River drainage divide area landform origins in the Standing Rock Indian Reservation, North and South Dakota, 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 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 Standing Rock Indian Reservation Cannonball River-Grand River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Standing Rock Indian Reservation Cannonball River-Grand  River drainage divide area location map

Figure 1: Standing Rock Indian Reservation Cannonball River-Grand  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 general location map for the Standing Rock Indian Reservation Cannonball River-Grand River drainage divide area (the Standing Rock Indian Reservation is not shown on figure 1, but will be shown on figure 2 below). The Cannonball River originates in southwest North Dakota south of Belfield, North Dakota and flows southeast until it joins Cedar Creek near Shields, North Dakota and then the Cannonball River flows northeast to join the south-oriented Missouri River as a barbed tributary. Cedar Creek is the major Cannonball River tributary shown on figure 1 and it begins in southwest North Dakota south of the Cannonball River source and flows southeast to almost reach the North Dakota-South Dakota border near Lemmon, South Dakota and then flows east and northeast to reach the Cannonball River at its elbow of capture near Shields. Cannonball River drainage basin landform evidence is addressed in a separate essay found under North Dakota Missouri Slop on the sidebar category list. The North Fork Grand River begins near Rhame, North Dakota and flows southeast to join the South Fork Grand River near Shadehill, South Dakota and the combined flow continues east as the Grand River, which flows to the south-oriented Missouri River. The South Fork Grand River originates southwest of Buffalo, South Dakota and flows northeast, east, and northeast to reach the North Fork at Shadehill Reservoir. Landform evidence along the North Fork-South Fork Grand River drainage divide is addressed in an essay found under SD Grand River on the sidebar category list. Note how the north-oriented Little Missouri River is located just west of the Grand River and Cannonball River source areas. The Standing Rock Indian Reservation includes the North Dakota-South Dakota border area from Thunder Hawk, South Dakota east to the Missouri River, which also approximates the Cedar Creek-Grand River and Cannonball River-Grand River drainage divide area location addressed here. This essay interprets Cannonball River-Grand River drainage divide area landform evidence in the context of an immense southeast oriented flood that flowed across southwest North Dakota and northwest South Dakota and was captured first by headward erosion of deep southeast and east-oriented valleys and subsequently by headward erosion of deeper northeast-oriented valleys and finally by headward erosion of the south-oriented Missouri River valley. Prior to headward erosion of the Grand River valley flood waters continued southeast over what is today the Grand River-Moreau River drainage divide. Other essays address landform evidence along the eastern Grand River-Moreau River drainage divide and along the South Fork Grand River-Moreau River drainage divide and can be found under SD Grand River and Moreau River on the sidebar category list.

Detailed Standing Rock Indian Reservation Cannonball River-Grand  River drainage divide area location map

Figure 2: Detailed Standing Rock Indian Reservation Cannonball River-Grand  River drainage divide area location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 illustrates the Standing Rock Indian Reservation Cedar Creek-Grand River drainage divide area and the Cannonball River-Grand River drainage divide area to be addressed here. Cedar Creek and the northeast oriented Cannonball River valley segment mark the Standing Rock Reservation northern border in North Dakota. The east oriented Grand River is located south of the North Dakota-South Dakota border and turns southeast just before flowing to the south-oriented Missouri River near Mobridge, South Dakota. Note the predominance of southeast-oriented Grand River tributaries and also the predominance of southeast-oriented tributaries to east and northeast oriented Cedar Creek and the northeast-oriented Cannonball River valley segment, as well as to the south-oriented Missouri River. These southeast-oriented tributaries are evidence that what are today northeast and east oriented major trunk stream valleys eroded headward to capture multiple southeast-oriented flood flow routes such as might be found in a large-scale southeast-oriented anastomosing channel complex. If so a simplified sequence of events based on figure 2 evidence would have the east-oriented Grand River valley eroding west first to capture the southeast-oriented flood and to divert the flood waters somewhere to the east. Subsequently the northeast-oriented Cannonball River-Cedar Creek valley would have eroded southwest and then west to behead southeast-oriented flood flow routes to the Grand River valley and to divert flood waters somewhere to the northeast. And finally headward erosion of the south-oriented Missouri River valley would have captured the Grand River and Cannonball River flood flow. This simplified sequence does not address all of the detailed evidence and the detailed maps and discussions below will try to address more of the detailed evidence. The detailed maps and discussions will begin in the west by looking at the Cedar Creek-Grand River drainage divide area near Thunder Hawk and then proceed east. The essay concludes with maps and discussions addressing North Dakota evidence in the area southeast of the northeast-oriented Cannonball River that is today drained by Missouri River tributaries.

Cedar Creek-Grand River drainage divide area near Thunder Hawk, South Dakota

Figure 3: Cedar Creek-Grand River drainage divide area near Thunder Hawk, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Cedar Creek-Grand River drainage divide area near Thunder Hawk, South Dakota. Thunder Hawk Creek in the figure 3 southwest corner flows to the east oriented Grand River. South-southwest-oriented East Thunder Hawk Creek originates south of Thunder Hawk and flows to Thunder Hawk Creek. In the figure 3 northwest corner are northwest-oriented headwaters of Plum Creek, which flows to east and northeast-oriented Cedar Creek. Willow Creek and the West Branch of Willow Creek in the figure 3 southeast corner flow southeast to the east oriented Grand River. East-oriented Hay Creek flows along the highway to Keldron and further east (see figure 4) will turn northeast to flow to east and northeast-oriented Cedar Creek. The northwest oriented Plum Creek valley originated as a southeast-oriented flood flow route to the Grand River valley and the southeast-oriented Willow Creek and West Branch Willow Creek valleys eroded headward along that flow route. Headward erosion of the east and northeast-oriented Cedar Creek-Hay Creek valley captured at least some, if not all of the southeast-oriented flood flow to the Willow Creek valley and diverted the flood flow to the newly eroded northeast-oriented Cannonball River valley. Headward erosion of the Cedar Creek valley north of the Hay Creek valley next beheaded southeast-oriented flood flow moving on the Plum Creek valley route to the Hay Creek valley and any remaining flood flow moving to the Willow Creek drainage basin. Flood waters on the northwest end of the beheaded flood flow route reversed their flow direction and began to flow northwest to the newly eroded and somewhat deeper Cedar Creek valley. This reversed flow, which may have been aided by flood waters captured from yet to be beheaded flood flow routes further to the west, eroded the northwest-oriented Plum Creek drainage basin and created the Plum Creek-Hay Creek drainage divide and the figure 3 map area Cedar Creek-Grand River drainage divide.

Cedar Creek-Grand River drainage divide area near Morristown, South Dakota

Figure 4: Cedar Creek-Grand River drainage divide area near Morristown, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Cedar Creek-Grand River drainage divide area east of the figure 3 map area and includes a very thin overlap strip. East-oriented Hay Creek follows the highway before turning northeast in the figure 4 north center and flows to east and northeast-oriented Cedar Creek and then to the northeast-oriented Cannonball River. Southeast of Morristown an unnamed northeast-oriented Hay Creek tributary flows to Morristown Lake and then northeast to northeast-oriented Hay Creek. In the figure 4 south center are headwaters of southeast-oriented Dirt Lodge Creek, which flows to the east oriented Grand River. In the figure 4 southeast corner south-southeast-oriented Red Willow Creek flows to southeast-oriented Dirt Lodge Creek and then to the Grand River. In the figure 4 northeast corner near Watauga are headwaters of southeast-oriented Hump Creek, which also flows to the east oriented Grand River. The southeast-oriented Hump Creek and Dirt Lodge Creek valleys and the tributary Red Willow Creek valley were probably eroded headward along southeast-oriented anastomosing flood eroded channels that had been captured by headward erosion of the deep east oriented Grand River valley. Note how the Hump Creek and Red Willow Creek headwaters are located in the same general region. This evidence suggests an anastomosing channel pattern prior to beheading of the southeast-oriented flood flow routes. The southeast-oriented flood flow was beheaded by headward erosion of the east and northeast-oriented Hay Creek valley, which probably eroded southwest and west from what was then an actively eroding east- and northeast-oriented Cedar Creek valley (and probably from a newly eroded northeast-oriented Cannonball River valley). Note northwest-oriented tributaries to the northeast-oriented Hay Creek segment east and northeast of Morristown. Those northwest-oriented tributaries are evidence flood flow on the northwest ends of beheaded southeast-oriented flood flow routes to what were then the actively eroding southeast-oriented Dirt Lodge Creek and Hump Creek valleys reversed flow direction and flowed northwest to the newly eroded and somewhat deeper northeast-oriented Hay Creek valley.

Cedar Creek-Grand River drainage divide area near McIntosh, South Dakota

Figure 5: Cedar Creek-Grand River drainage divide area near Thunder Hawk, South DakotaUnited States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Cedar Creek-Grand River drainage divide area east of the figure 5 map area and includes an overlap strip. Along the figure 5 south edge from west to east major southeast-oriented Grand River tributaries are Hump Creek (southwest corner), White Shirt Creek (south center) and Stink Creek, with headwaters of southeast-oriented Iron Dog Creek (a Stink Creek tributary) flowing to the figure 5 southeast corner. Named north and northwest-oriented Cedar Creek tributaries from west to east are Timber Creek, Plum Creek, and Roger Creek, with headwaters of an unnamed northwest-oriented Cedar Creek tributary located in the figure 5 northeast corner. Events recorded by this figure 5 evidence are similar to events recorded by the previous figure evidence. Multiple southeast-oriented flood flow routes, probably a southeast-oriented anastomosing channel complex, flowed across the figure 5 map area, probably on a topographic surface at least as high as the highest points along the drainage divide today. The southeast-oriented flood flow routes had probably been captured by headward erosion of the deep east-oriented Grand River valley to the south and the Iron Dog Creek, Stink Creek, White Shirt Creek, and Hump Creek valleys were eroding headward along southeast-oriented flood flow channels. At approximately the same time headward erosion of the deep northeast-oriented Cannonball River-Cedar Creek valley began to systematically behead the southeast-oriented flood routes (from northeast to southwest) and to divert captured flood waters to the northeast. Flood waters on the northwest ends of beheaded flood flow routes reversed direction to flow northwest to the newly eroded and deeper northeast-oriented Cedar Creek-Cannonball River valley. By doing so the reversed flood waters created the present day north-and northwest-oriented Cedar Creek tributary drainage basins and also created the figure 5 map area Cedar Creek-Grand River drainage divide.

Cannonball River-Grand River drainage divide area near Walker, South Dakota

Figure 6: Cannonball River-Grand River drainage divide area near Walker, South Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Cannonball River-Grand River drainage divide area east of the figure 5 map area and includes an overlap strip (note, digital maps at the scale used here do not include most contour lines for some figure 6 map areas). Northwest-oriented drainage in the figure 6 northwest quadrant are headwaters of northwest-oriented Leaf on the Hill Creek, which flows to the northeast-oriented Cannonball River. South-oriented drainage west of Walker flows to southeast oriented Iron Dog Creek, which is a tributary of southeast oriented Stink Creek and the east and southeast oriented Grand River. South-southeast-oriented Rock Creek flows to the east and southeast-oriented Grand River. Southeast-oriented Oak Creek flows directly to the Missouri River and joins the Missouri River just north from where the Grand River joins the Missouri River and for purposes of this discussion will be treated as a Grand River tributary. The sequence of figure 6 map area events is similar to the figure 5 event sequence. Flood waters first moved southeast across the figure 6 map area probably on a topographic surface at least as high as the highest Cannonball River-Grand River drainage divide region elevations today. Headward erosion of the deep southeast- and east-oriented Grand River valley then captured the southeast-oriented flood flow and diverted flood waters somewhere to the east. Southeast-oriented tributary valleys then began to erode headward from the deep Grand River valley along flood flow routes probably associated with southeast-oriented channels in a flood formed anastomosing channel complex. These southeast-oriented valleys included the Oak Creek valley, the Rock Creek valley, and the Stink Creek-Iron Dog Creek valleys. Flood flow to these actively eroding southeast-oriented valleys was then beheaded systematically from the northeast to the southwest by headward erosion of the deep northeast-oriented Cannonball River valley. Flood flow on the northwest ends of the beheaded flood flow routes then reversed flow direction to erode the northwest-oriented Cannonball River tributary drainage basins and to create the present day Cannonball River-Grand River drainage divide.

Porcupine Creek-Oak Creek drainage divide area near Selfridge, North Dakota

Figure 7: Porcupine Creek-Oak Creek drainage divide area near Selfridge, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Porcupine Creek-Oak Creek drainage divide northeast of the figure 6 map area and there is overlap between the figure 7 southwest corner and the figure 6 northeast corner (note, digital maps at the scale used here do not include contour lines for the figure 7 southwest corner). Porcupine Creek flows northwest from Selfridge, North Dakota. Oak Creek flows southeast across the figure 7 southwest corner and an Oak Creek tributary flows south-southeast from the Selfridge area. Fourmile Creek flows east in the figure 7 southeast quadrant. Porcupine Creek  flows northwest in a large northwest-southeast-oriented through valley that in various forms extends northwest across the Cannonball River drainage basin, the Heart River drainage basin, the Knife River drainage basin, and the Little Missouri River drainage basin. Essays describing the Cannonball River drainage basin, eastern Heart River drainage basin, Knife River drainage basin, and Little Missouri River-Knife River drainage divide all illustrate segments of this northwest-southeast-oriented through valley and can be found under North Dakota Missouri Slope on the sidebar category list. Apparently this northwest-southeast-oriented through valley location was defined by southeast-oriented flood waters prior to headward erosion of the northeast-oriented Cannonball River, Heart River, and Knife River valley segments and prior to headward erosion of the deep north and east-oriented Little Missouri River valley, although initially the southeast-oriented flood flow route may have been across a much higher topographic surface than exists today. The northwest-southeast-oriented through valley was systematically beheaded by headward erosion of the northeast-oriented Cannonball River valley, the northeast-oriented Heart River valley, the northeast-oriented Knife River valley, and the deep Little Missouri River valley, in that order. Prior to capture by the northeast-oriented Cannonball River valley there were capture events in the present day Porcupine Creek area, which will be discussed below. The north-northwest oriented Porcupine Creek valley seen in figure 7 represents a reversal of flood flow following one of those early capture events that created what is today a very unusual Porcupine Creek course.

Porcupine Creek drainage basin area in North Dakota

Figure 8: Porcupine Creek drainage basin area in North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 illustrates the Porcupine Creek drainage route north of the figure 7 map area and includes significant overlap areas. The north-northwest-oriented Porcupine Creek valley seen in figure 7 is in figure 8 turning northeast and making a U-turn to flow southeast, east, and then southeast again. Figure 10 will show where Porcupine Creek joins the south-oriented Missouri River upstream from Fort Yates, North Dakota. How did the Porcupine Creek valley U-turn evolve? As previously mentioned the northwest-oriented Porcupine Creek valley segment is aligned with a major northwest-southeast-oriented through valley. That through valley was (at least in the Cannonball River-Grand River region) not a single valley, but an anastomosing complex of southeast-oriented valleys. Northwest of the southeast-oriented Porcupine Creek valley segment is a through valley crossing the Cannonball River-Porcupine Creek drainage divide and multiple links to through valleys continue further to the northwest. Evidence presented in this essay does not indicate where flood waters flowing in the anastomosing channel complex were going, but probably it was similar to where flood waters that eroded the east and southeast-oriented Grand River valley were also flowing. The flood waters were going some place that had a base level significantly lower than the topographic surface that prevailed across the figure 8 region at that time, which was probably at least as high as the highest Porcupine Hills elevations today. The lower base level meant deep southeast-oriented valleys eroded headward along the southeast-oriented anastomosing channels and because the anastomosing channels intertwined the deep valleys did likewise and the modern-day northeast-oriented Porcupine Creek valley segment was probably eroded as southwest-oriented valley connecting two southeast-oriented anastomosing valleys. Erosion of the southwest-oriented valley enabled the southeast-oriented Porcupine Creek valley segment to capture southeast-oriented flood flow from the more westerly valley (the present day northwest-oriented Porcupine Creek valley). That capture reversed flow on what had been a southwest-oriented valley so it became a northeast-oriented valley. The capture probably reversed flow on the northwest end of the more westerly valley to create the northwest-oriented Porcupine Creek-southeast-oriented Oak Creek drainage divide seen in figure 7. Subsequently the deep northeast-oriented Cannonball River valley eroded southwest (north of the figure 8 map area) and captured all of the southeast-oriented flood flow to the present day Porcupine Creek drainage basin area.

Cannonball River-Porcupine Creek drainage divide area southwest of Cannonball, North Dakota

Figure 9: Cannonball River-Porcupine Creek drainage divide area southwest of Cannonball, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Cannonball River-Missouri River confluence area northeast of the figure 8 map area and includes overlap areas. The northeast-oriented Cannonball River flows from the figure 9 west center to join the south-oriented Missouri River in the figure 9 northeast corner. Note the short northwest-oriented tributaries flowing the Cannonball River especially between Breien and Solen, North Dakota. The Porcupine Creek elbow of capture (where it turns from flowing northeast to flowing southeast) is located in the figure 9 southwest corner. The southeast oriented Battle Creek drainage basin south of Solen is located between the southeast oriented Porcupine Creek drainage basin and the northeast-oriented Cannonball River drainage basin. Beaver Holes Creek flows southeast in the figure 9 east center. The southeast oriented Battle Creek valley was probably initiated as part of the previously mentioned anastomosing channel complex of the which the present day southeast and northwest oriented Porcupine Creek valleys were also components. Note through valleys linking the southeast-oriented Battle Creek valley with the northeast-oriented Cannonball River valley. Those multiple through valleys were probably eroded by anastomosing southeast-oriented channels prior to headward erosion of the northeast-oriented Cannonball River valley. The Beaver Holes Creek valley probably was also an anastomosing channel complex component as well, although the evidence is not as easy to identify on figure 9. Evidence presented in the essay is not adequate to determine where flood waters captured by northeast-oriented Cannonball River valley headward erosion were going, but the today the Cannonball River enters the Missouri River as a barbed tributary, which suggests the flood waters were going to a location further to the north and east than the present day Cannonball River-Missouri River confluence area.

Porcupine Creek-Missouri River confluence area near Fort Yates, North Dakota

Figure 10: Porcupine Creek-Missouri River confluence area near Fort Yates, North Dakota. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 illustrates the Porcupine Creek drainage route east of figures 7 and 8 and includes overlap areas with those figures. Southeast-oriented Porcupine Creek flows to the south-oriented Missouri River in the figure 10 north center located north of Fort Yates, North Dakota and southeast-oriented Battle Creek joins the Missouri River a short distance upstream in the figure 10 northeast quadrant. Fourmile Creek flows east and east-northeast to the south-oriented Missouri River along the figure 10 south edge. Note the northwest-oriented stream flowing to the south-oriented Missouri River as a barbed tributary just southeast of Winona Flats. That northwest-oriented stream is unnamed on figure 10, but is Cattail Creek and the Cattail Creek valley is linked by through valleys to other valleys in the southeast suggesting it was another component of the “original” southeast-oriented anastomosing channel complex that eroded northwest-southeast-oriented valleys headward into the figure 8, 9, and 10 map areas. Fourmile Creek enters the Missouri River as a barbed tributary suggesting the Fourmile Creek valley orientation was established prior to headward erosion of the south-oriented Missouri River valley. If so the Fourmile Creek valley probably eroded headward from what was a deep southeast-oriented valley being eroded headward along the Cattail Creek-Porcupine Creek valley alignment seen in figure 10. Apparently the southeast-oriented valley being eroded along this alignment was significantly deeper than the southeast-oriented valley being eroded along what is today the Oak Creek-northwest-oriented Porcupine Creek alignment seen in figure 7 and the Fourmile Creek valley eroded west to capture southeast oriented flood flow on that more westerly flood flow route. However, before the Fourmile Creek valley could capture all of the western route flood flow headward erosion of the southeast-oriented Porcupine Creek valley captured the flood flow further to the northwest and caused a reversal of flood flow in what is today the northwest-oriented Porcupine Creek valley. Subsequently the northeast-oriented Cannonball River captured all southeast-oriented flood flow across the figure 10 map area and then the south-oriented Missouri River valley eroded north and captured the northeast-oriented flood flow, which suggests significant amounts of flood water were spilling south for reasons not evident from evidence presented here.

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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