Powder River-Belle Fourche River drainage divide area landform origins, northeast Wyoming, USA

· Belle Fourche River, Powder River, Wyoming
Authors

A geomorphic history based on topographic map evidence

Abstract:

The Powder River-Belle Fourche River drainage divide area discussed here is located in Wyoming’s northeast quadrant. Although detailed topographic maps of this Powder River-Belle Fourche 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. This Powder River-Belle Fourche 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 ended when headward erosion of the north-oriented Powder 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 northeast Wyoming  Powder River-Belle Fourche 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 northeast Wyoming Powder River-Belle Fourche River drainage divide area landform evidence will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm.

Powder River-Belle Fourche River drainage divide area general location map

Figure 1: Powder River-Belle Fourche River drainage divide area general location map. National Geographic Society map digitally presented using National Geographic Society TOPO software.

Figure 1 illustrates the Powder River-Belle Fourche River drainage divide area in northeast Wyoming. The Powder River begins in central Wyoming and flows north and northeast to Montana where it joins the northeast-oriented Yellowstone River. The Belle Fourche River begins south of Gillette, Wyoming and flows northeast almost to the Montana state line and then abruptly turns to flow southeast into South Dakota where it joins the northeast-oriented Cheyenne River to flow to the south and southeast-oriented Missouri River. In Wyoming’s northeast corner between the Powder River drainage basin and the northeast-oriented Belle Fourche River segment is the northeast-oriented Little Missouri River, which flows northeast across the Montana southeast corner and then into South Dakota and later North Dakota, where it joins the south oriented Missouri River. Southeast of the northeast-oriented Belle Fourche River segment are southeast-oriented tributaries flowing to the southeast-oriented Cheyenne River, which after flowing around the Black Hills south end turns northeast to join with the southeast-oriented Belle Fourche River segment and flow to the south and southeast-oriented Missouri River. Several Powder River tributaries begin in the Bighorn Mountains and west of the Bighorn Mountains is the north-oriented Bighorn River, which flows to the northeast-oriented Yellowstone River. In northern Wyoming and in Montana between the Bighorn River and the Powder River drainage basins is the northeast-oriented Tongue River drainage basin. This essay interprets Powder River-Belle Fourche River drainage divide landform evidence as depicted on detailed topographic maps shown here to have been formed during immense southeast-oriented flood events that were first captured by headward erosion of the northeast-oriented Belle Fourche River valley segment and subsequently captured by headward erosion of the north-oriented Powder River and its tributary Little Powder River valleys. The flood source cannot be determined from evidence presented here, although by using many of the essays published on this website it is possible to trace flood waters headward to a North American ice sheet location. Rapid melting of a thick North American ice sheet, which through its weight and erosive actions created a “hole” in the North American continent and caused crustal warping elsewhere on the continent, would be a logical flood water source.

Powder River-Belle Fourche River drainage divide area detailed location map

Figure 2: Powder River-Belle Fourche River 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 Powder River-Belle Fourche River drainage divide area to be discussed here. The Powder River flows north in the figure 2 west quadrants and the Belle Fourche River flows northeast from the Pumpkin Buttes area (figure 2 south center west) toward the figure 2 northeast corner. The Little Powder River (a Powder River tributary) flows north and north-northwest in the figure 2 north center east. Powder River tributaries from the east are usually northwest-oriented and Belle Fourche River tributaries from the northwest are usually southeast oriented. Belle Fourche River tributaries from the southeast are usually northwest-oriented and shorter Powder River tributaries from the west are southeast oriented. Longer Powder River tributaries from the west are northeast-oriented, but tributaries to those longer Powder River tributaries tend to be southeast- and northwest-oriented. Cheyenne River tributaries flowing from the Belle Fourche River-Cheyenne River drainage divide tend to be southeast-oriented. This northwest-southeast oriented drainage alignment is evidence the northeast-oriented Belle Fourche River valley eroded headward to capture multiple southeast-oriented flood flow channels, typical of channels that might be found in a large-scale anastomosing channel complex, and diverted the southeast-oriented flood flow to the northeast and subsequently the north-oriented Powder River valley eroded south to capture the southeast-oriented flood water and to divert the flood water north. Evidence illustrated in the detailed maps below will further support this interpretation. Evidence presented here begins at the northeast end of the Powder River-Belle Fourche River drainage divide and proceed southwest to the Pumpkin Buttes area where the Belle Fourche River begins.

Mitchell Creek-Belle Fourche River drainage divide area

Figure 3: Mitchell Creek-Belle Fourche River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Powder River-Belle Fourche River drainage divide northeast end. The northeast-oriented Little Missouri River originates just north of the figure 3 north center edge and flows between the north-oriented Little Powder River (a Powder River tributary) and the northeast-oriented Belle Fourche River segment. Separate essays discuss Wyoming’s Little Powder River-Little Missouri River drainage divide landform evidence and Wyoming’s Little Missouri River-Belle Fourche River drainage divide landform evidence and can be found under Little Missouri River on the sidebar category list. The northwest-oriented Mitchell Creek and Cottonwood Creek drainage systems flow to the north-oriented Little Powder River and then to the Powder River. Cabin Creek flows east to the northeast-oriented Belle Fourche River while the southeast-oriented Miller Creek drainage system (including Crazy Creek) also flows to the northeast-oriented Belle Fourche River. The previously discussed northwest-southeast oriented drainage alignment can be seen on both sides of the Powder River-Belle Fourche drainage divide, which extends in a north-northeast direction between the two major drainage basins. Close study of the drainage divide reveals shallow through valleys link heads of northwest-oriented streams with the southeast-oriented streams. These through valleys are evidence water once flowed in a southeast direction across the drainage divide, not just in one channel, but in multiple channels. The best way to view the figure 3 evidence is to imagine a flood of southeast-oriented flood water flowing along the present day Mitchell Creek valley and splitting into diverging channels to flow across the present day Powder River-Belle Fourche River drainage divide and then to flow in converging channels to the Miller Creek valley and then to flow to what was then the newly eroded northeast-oriented Belle Fourche River valley. While this view is probably overly simplistic it does illustrate the figure 3 evidence for what was probably an ever-changing complex of anastomosing flood flow channels that crossed the present day drainage divide and that was beheaded when the Little Powder River valley eroded south, diverted the flood water north, caused a reversal of flood flow on the northwest ends of the beheaded southeast-oriented flood flow channels, and created the Powder River-Belle Fourche River drainage divide.

Little Powder River-Donkey Creek drainage divide area

Figure 4: Little Powder River-Donkey Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates a Powder River-Belle Fourche River drainage divide region southwest of the figure 3 map area. Headwaters of north-oriented Cottonwood Creek (seen in figure 3 west edge) flow north to the figure 4 north center. Cottonwood Creek after flowing north across the figure 3 map area turns northwest to join the north-oriented Little Powder River. Northwest-oriented headwaters of the northwest and north-oriented Little Powder River can be seen along the figure 4 west center edge. East-oriented Donkey Creek flows along the figure 4 south edge and flows to the northeast-oriented Belle Fourche River near Moorcroft, Wyoming (see figure 2). Note southeast-oriented tributaries flowing to the east-oriented Donkey Creek and then the northeast-oriented Belle Fourche River. These southeast-oriented tributaries are relics of southeast-oriented flood flow channels or routes that were captured by headward erosion of the northeast-oriented Belle Fourche River valley and its tributary Donkey Creek valley. Note how headwaters of these southeast-oriented Donkey Creek tributaries are linked to northwest-oriented tributaries of Cottonwood Creek and the Little Powder River. Through valleys linking the northwest-oriented streams with the southeast-oriented are further evidence multiple channels or flood water routes once carried southeast-oriented flood water across the present day Powder River-Belle Fourche River drainage divide. Finally note how a northeast-oriented Cottonwood Creek valley segment has eroded southwest to near the present day Little Powder River origin and today has southeast-oriented and northwest-oriented tributaries. The figure 3 evidence can be explained in the following sequence of events. First southeast-oriented flood water flowing in multiple channel crossed the entire figure 4  map area. Second the east-oriented Donkey Creek valley eroded west from the newly eroded northeast-oriented oriented Belle Fourche River valley. Third, headward erosion of the north-oriented Little Powder River valley beheaded southeast-oriented flood flow on the Mitchell Creek-Cottonwood Creek alignment (figure 3) and caused a reversal of flood flow on that alignment. Fourth, headward erosion of the north-oriented Cottonwood Creek valley caused by the reversal of flood flow on the Cottonwood Creek-Mitchell Creek northwest-oriented segment  alignment captured flood flow further to the southwest on yet to be beheaded (by Little Powder River valley headward erosion) southeast-oriented flood flow routes. Fifth, the Cottonwood Creek valley eroded southwest to capture flood flow on more of the yet to be beheaded southeast-oriented flood flow routes and in the process caused reversals of flood flow on the northwest ends of beheaded flow routes to create northwest-oriented Cottonwood Creek tributaries and the Cottonwood Creek-Donkey Creek drainage divide. Sixth, Little Powder River valley headward erosion captured all southeast-oriented flood flow routes, caused reversal of flood flow on the northwest ends of beheaded flood flow routes, and created the present day Little Powder River-Cottonwood Creek drainage divide.

Powder River-Little Powder River-Donkey Creek drainage divide area

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

Figure 5 illustrates a Powder River-Belle Fourche drainage divide region west of the map 4 area. East-oriented Donkey Creek is south of Gillette, Wyoming and flows to the northeast-oriented Belle Fourche River near Moorcroft, Wyoming (see figure 2). West of Gillette east-oriented Donkey Creek headwaters are linked to northwest-oriented Rawhide Creek headwaters. North of figure 5 Rawhide Creek turns northeast and flows to the north-oriented Little Powder River. North of Gillette is northwest-oriented Little Rawhide Creek, which north of figure 5 turns northeast and flows to northeast-oriented Rawhide Creek, which in turn flows to the Little Powder River. West of the east-oriented Donkey Creek headwaters and south of northwest-oriented Rawhide Creek in the figure 5 southwest quadrant are northwest-oriented headwaters of Wild Horse Creek tributaries. Wild Horse Creek flows northwest to the Powder River. The sequence of events depicted by figure 5 evidence begins with southeast-oriented flood water probably flowing in an ever-changing anastomosing channel complex across the figure 5 map area. Next headward erosion of the northeast-oriented Belle Fourche River and east-oriented Donkey Creek valley captured the southeast-oriented flood water and caused reversals on the northwest ends of beheaded flood flow routes (see southeast corner figure 5). Next headward erosion of the north-oriented Little Powder River and northeast-oriented Rawhide Creek and Little Rawhide Creek valleys (north of figure 5) beheaded southeast-oriented flood flow routes to Donkey Creek and caused a reversal of flood flow on those routes to create the northwest-oriented Rawhide Creek and Little Rawhide Creek tributaries and to create the Rawhide Creek-Donkey Creek drainage divide. Finally headward erosion of the north-oriented Powder River valley beheaded the final southeast-oriented flood flow routes to the Donkey Creek drainage basin and caused a reversal of flood flow on those routes to create the northwest-oriented Wild Horse Creek drainage basin and the present day Wild Horse Creek-Donkey Creek drainage divide.

Wild Horse Creek-Bone Pile Creek drainage divide area

Figure 6: Wild Horse Creek-Bone Pile Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates a Powder River-Belle Fourche River drainage divide region southwest of the figure 5 map area (with overlap). In the northeast quadrant east-oriented Donkey Creek flows to the northeast-oriented Belle Fourche River near Moorcroft, Wyoming (see figure 2). Northwest-oriented drainage routes are to northwest-oriented Wild Horse Creek, which flows to the north-oriented Powder River. In the figure 6 southwest quadrant west-oriented drainage flows to northwest-oriented Dead Horse Creek, which flows to the north-oriented Powder River. Southeast-oriented drainage flows to southeast-oriented Bone Pile Creek, which flows to the northeast-oriented Belle Fourche River. Bluegate Creek (figure 6 south center) turns southeast and flows directly to the northeast-oriented Belle Fourche River. Events recorded by figure 6 evidence begin with a southeast-oriented anastomosing channel complex carrying flood waters across the entire figure 6 map region. Headward erosion of the northeast-oriented Belle Fourche River-Donkey Creek valley next captured southeast-oriented flood waters and caused reversals of flood flow on northwest ends of beheaded flood flow routes. Headward erosion of the northeast-oriented Belle Fourche River valley next captured southwest-oriented flood water from flood flow routes that had not been beheaded by Donkey Creek headward erosion (e.g. Wild Horse Creek-Bone Pile Creek alignment). Next headward erosion of the north-oriented Powder River valley beheaded and captured southeast-oriented flood flow on the Wild Horse Creek-Bone Pile Creek alignment and caused a reversal of flood flow on the northwest end of that beheaded flood flow route to create the northwest-oriented Wild Horse Creek valley and also the Wild Horse Creek-Bone Pile Creek drainage divide. For a time southeast-oriented flood flow continued to move southeast on the yet to be beheaded Dead Horse Creek alignment and some of that flood water was captured by headward erosion of the Bluegate Creek valley and some of the water probably spilled into the reversed flood flow on the Wild Horse Creek route (and helped erode the northwest-oriented Wild Horse Creek valley). Finally headward erosion of the north-oriented Powder River valley beheaded all southeast-oriented flood flow reaching the figure 6 map area and the regional landscape has changed little since.

Dead Horse Creek-Caballo Creek drainage divide area

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

Figure 7 illustrates a Powder River-Belle Fourche River drainage divide region southwest of the figure 6 map area (with some overlap). In the figure 7 northeast quadrant southeast-oriented Bone Pile Creek and Bluegate Creek flow to the northeast-oriented Belle Fourche River (southeast of figure 7 map area). South of Bluegate Creek east-oriented Caballo Creek and its east-oriented Hoe Creek tributary also flow to the northeast-oriented Belle Fourche River. West of the Powder River-Belle Fourche River drainage divide northwest-oriented streams are headwaters of northwest-oriented Dead Horse Creek while southwest-oriented Charlie Draw (figure 5 southwest corner) flows to northwest-oriented Beaver Creek. Both Dead Horse Creek and Beaver Creek flow to the north-oriented Powder River. Events recorded by figure 6 evidence again begin with an anastomosing complex of channels carrying southeast-oriented flood water across the region to what was then the newly eroded northeast-oriented Belle Fourche River valley. Headward erosion of the north-oriented Powder River valley next began to behead southeast-oriented flood flow routes moving through the present day Wild Horse Creek drainage basin and the Caballo Creek valley (and its Hoe Creek tributary valley) eroded west to capture flood flow from yet to be beheaded southeast-oriented flood flow routes. At the same time flood waters on the northwest ends of the beheaded flood routes began to reverse their flow direction and flow northwest to the newly eroded Powder River valley, This reversed flow began to erode the northwest-oriented Wild Horse Creek drainage basin and to create the Wild Horse Creek-Bluegate Creek drainage divide and then the Wild Horse Creek-Caballo Creek drainage divide. For a time flood water continued to move southeast on the yet to be beheaded Beaver Creek alignment and Charlie Draw (and various northeast-oriented Hoe Creek tributaries) originated where those continuing southeast-oriented flood waters were captured and diverted northeast to both flow northwest on the reversed Wild Horse Creek route and east to the northeast-oriented Belle Fourche River on the Hoe Creek-Caballo Creek route. Finally headward erosion of the Powder River valley beheaded all southeast-oriented flood flow moving to the figure 7 map area and flood flow on the northwest ends of the beheaded flow routes reversed flow direction to flow to the newly eroded north-oriented Powder River valley. Charlie Draw was eroded by reversed flood water flowing southwest to reach reversed flood water on what was then the newly reversed Beaver Creek flood flow route.

Pumpkin Creek-Belle Fourche River drainage divide area

Figure 8: Pumpkin Creek-Belle Fourche River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 continues the journey south along the Powder River-Belle Fourche River drainage divide and illustrates a region southwest of the figure 7 map area (with a very small strip of overlap). In the figure 8 northwest quadrant northwest-oriented streams are headwaters of northwest-oriented Beaver Creek flowing to the north-oriented Powder River. South of the northwest-oriented Beaver Creek drainage basin are northwest-oriented Pumpkin Creek tributaries flowing to northwest-oriented Pumpkin Creek and the north-oriented Powder River. East of the drainage divide in the figure 8 northeast quadrant southeast-oriented Threemile Creek flows to the northeast-oriented Belle Fourche River. South of the Threemile Creek drainage basin east and southeast-oriented Wild Horse Creek also flows to the northeast-oriented Belle Fourche River. Evidence here is similar to evidence in previous figures and includes the northwest-southeast oriented drainage alignment and shallow through valleys crossing the Powder River-Belle Fourche River drainage divide. This evidence can best be explained by the following sequence of events. First an anastomosing complex of channels carried southeast-oriented flood water across the entire figure 8 map region to the newly eroded northeast-oriented Belle Fourche River valley. Next headward erosion of the north-oriented Powder River valley beheaded the southeast-oriented flood flow routes to cause flood water on the northwest ends of the beheaded flood flow routes to reverse flow direction and to flow northwest to the newly eroded Powder River valley and in the process to erode the northwest-oriented Powder River tributary valleys and to create the present day Powder River-Belle Fourche River drainage divide.

Powder River-Belle Fourche River drainage divide in north Pumpkin Buttes area

Figure 9: Powder River-Belle Fourche River drainage divide in north Pumpkin Buttes area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Continuing south along the Powder River-Belle Fourche River drainage divide figure 9 illustrates a region south of the figure 8 map area (with no overlap). Northeast-oriented drainage east of the Pumpkin Buttes flows to the northeast-oriented Belle Fourche River. Willow Creek flows west between North Pumpkin Butte and the North Middle Pumpkin Butte and then turns northwest to flow to the north-oriented Powder River. The North Prong of Willow Creek flows southwest along the North Butte northwest base. The flat-topped Pumpkin Buttes are probably capped by some type of resistant caprock and today remain as erosional residuals after all surrounding material has been removed. Most likely southeast-oriented flood waters that crossed the region originally flowed on a topographic surface at least as high as the Pumpkin Buttes tops and the flood waters were responsible for the removal of the surrounding materials. Most evidence of the intervening events has been removed, but remaining evidence suggests the following events. First southeast-oriented flood water moved across the entire region across what is now the Belle Fourche River drainage basin into what is now the Cheyenne River drainage basin. Headward erosion of immense headcuts stripped the bedrock surface headward or northwest while headward erosion of a deep and broad northeast-oriented Belle Fourche River valley headcut eroded southwest. The Belle Fourche headcut reached the Pumpkin Buttes area where it encountered the resistant caprock material. At approximately the same time headward erosion of a deep and broad north-oriented Powder River valley headcut eroded south. The Belle Fourche valley erosion first beheaded and captured southeast-oriented flood flow going to what is now the Cheyenne River drainage basin. Headward erosion of the Powder River valley headcut next beheaded and captured southeast-oriented flood flow going to the northeast-oriented Belle Fourche River drainage route. Northwest-oriented Willow Creek and its southwest-oriented North Prong and the present day Powder River-Belle Fourche River drainage divide were created when flood waters on the northwest ends of beheaded southeast-oriented flood flow reversed their flow direction to flow northwest to the newly eroded Powder River valley.

Powder River-Belle Fourche River drainage divide in south Pumpkin Buttes area

Figure 10: Powder River-Belle Fourche River drainage divide in south Pumpkin Buttes area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 completes the journey south along the Powder River-Belle Fourche River drainage divide and illustrates the region south of the figure 9 map area (with no overlap). The northeast-oriented South Prong east of Pine Tree is the South Prong of the northeast-oriented Belle Fourche River and represents the southwest origin of the Belle Fourche River drainage system. Remember, the Belle Fourche River flows northeast almost to the Montana state line (see figure 1) and then turns southeast to join what east of the Black Hills is the northeast-oriented Cheyenne River (see essays under Cheyenne River on the sidebar category list). East and northeast-oriented drainage routes north of the South Prong flow to the northeast-oriented Belle Fourche River. Southeast-oriented Bates Creek (figure 10 southeast corner) flows eventually to the southeast-oriented Cheyenne River west of the Black Hills. Northwest-oriented drainage routes flow to the north-oriented Powder River. Events recorded by landform evidence in the figure 10 map area suggest flood waters initially flowed southeast across the map region, probably on a topographic surface at least as high as the top of South Butte. Headward erosion of a series of immense southeast-oriented Cheyenne River and tributary valley headcuts began to strip the regional landscape as did headward erosion of a series of immense northeast-oriented Belle Fourche River and tributary valley headcuts and headward erosion of a series of immense north-oriented Powder River valley and tributary valley headcuts. Headward erosion of the these three immense headcut systems all reached the figure 10 map area at approximately the same time, although the Powder River valley being west of the other two was able to capture all of the flood flow, causing a reversal of flood flow on the northwest ends of beheaded flood flow routes to create the present day northwest-oriented Powder River tributary valleys and the Powder River-Belle Fourche River drainage divide (and the Powder River-Cheyenne River drainage divide).

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 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.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: