Journal Entry: July 19, 1805
 
Quotation from Lewis  [DeVoto, pp. 159-160]:
     this morning we set out early and proceeded on very well tho' the water appears to encrease in volocity as we advance. the current has been strong all day and obstructed with some rapids, tho' these are but little broken by rocks and are perfectly safe.  the river deep and from 100 to 150 yds. wide.  I walked along shore today and killed an Antelope. wh[en]ever we get a view of the lofty summits of the mountains the snow presents itself, altho' we are almost suffocated in this confined valley with heat. this evening we entered much the most remarkable clifts that we have yet seen. these clifts rise from the waters edge on either side perpendicularly to the hight of 1200 feet. every object here wears a dark and gloomy aspect. the towering and projecting rocks in many places seem ready to tumble on us. the river appears to have forced it's way through this immence body of solid rock for the distance of 5 3/4 Miles and where it makes it's exit below has thrown on either side vast collumns of rocks mountains high.
     the river appears to have woarn a passage just the width of it's channel or 150 yds.  it is deep from side to side nor is there in the 1st 3 Miles of this distance a spot except one of a few yards in extent on which a man could rest the soal of his foot.  several fine springs burst out at the waters edge from the interstices of the rocks.  it happens fortunately that altho' the current is strong it is not so much so but what it may be overcome with the oars for there is hear no possibility of using either the ord or Setting pole.  it was late in the evening before I entered this place and was obliged to continue my rout untill sometime after dark before I found a place sufficiently large to encamp my small party; at length  such an one occurred on the lard. side where we found plenty of lightwood and pich pine.  this rock is a black grannite below and appears to be of a much lighter colour above and from the fragments I take it to be flint of a yellowish brown and light creem-coloured yellow. from the singular appearance of this place I called it the gates of the rocky mountains.


Quotation from Clark [DeVoto, pp. 160-161]:

I proceeded on in an Indian Parth    river verry Crooked    passed over two mountains    Saw Several Indians Camps which they have left this Spring. Saw trees Peeled & found poles &c.  at 11 oC. I saw a gange of Elk, as we had no provision Concluded to kill Some.  Killd. two and dined being obliged[d] to substitute dry buffalow dung in place of wood,   this evening passed over a Cream Coloured flint which [has] roled down from the Clifts into the bottoms, the Clifts Contain flint a dark grey Stone & a redish brown intermixed and no one Clift is solid rock,    all the rocks of everry description is in Small pi[e]ces, appears to have been broken by Some Convulsion    my feet is verry much brused & cut walking over the flint & constantly stuck full [of] Prickley pear thorns,   I puled out 17 by the light of the fire to night   Musqutors verry troublesom.

Digital Elevation Models offer one view of the terrain.  Digital Chart of the World.  Contour interval of 1000 feet.  The Gates of the Rocky Mountains are shown as a red dot.

The Digital Chart of the World (from ESRI) offers contours at a 1000 foot contour interval.  Creation of a Triangulated Irregular Network from these contours permits visualization of a chunky terrain and offers a general context in which to consider the region.  (Click on the small map to see a larger map.)

USGS contours show a much more detailed picture than does the Digital Chart of the World.

Triangulated Irregular Network created from the USGS DEM.

Digitized contours at the 100 foot contour interval level.	Triangulated Irregular Network made from digitized contours.
Missouri River superimposed in light cyan.	The Gates of the Rocky Mountains, red dot.

Each type of base topographic map has merits:  the 1000 foot contour interval map is useful, especially when represented as a TIN, as a general context map.  When the finest contour interval (10 feet) was used, the general context was not evident.  The TIN derived from the contour base shows great detail.  The 100 foot contour interval offers a balance between the two.  That map, however, was not a digitized map that would work directly in a GIS (ArcView, ESRI).  Thus, the contours were digitized from the 100 foot base map, a TIN created from that base, and then the TIN was put into ArcView 3D Analyst extension (ESRI) and saved as VRML 2.0, as a virtual reality of the scene.  The much more highly detailed USGS file renders a fine virtual reality scene; however, the size of that file is over 177 MB and it causes many machines to crash.  Thus, the more modest file of 3 MB created from the 100 foot contour interval map is included here. Readers should download (free) Cosmo Player from http://ca.com/cosmo/ in order to view the virtual reality files directly in their internet browser.
 
 

What else might illuminate historical and geographical texts of the future, as an exploration in imaginative interactive communication and education?
One might envision

• creating routes and scenes, defined by the user, in support of text.  (See, for example, the outstanding display created at the Department of Geography, University of Missouri in the attached link)
• taking virtual voyages in canoes up the Missouri River  as a search (using a search function) of the landscape for animated local sentinels, all while music of the period is playing in the background.
• creating a virtual Mandan village, as a way for present day Americans to view one of the most important trading communities of the period.

References

DeLorme, Topographic Atlas on CD.  http://www.delorme.com/

DeVoto, Bernard.  The Journals of Lewis and Clark with a foreword by Stephen E. Ambrose, maps by Erwin Raisz.   Mariner Books, Houghton Mifflin Company (Boston and New York), original copyright 1953; current version, 1997.

Digital Chart of the World.  Environmental Systems Research Institute, http://www.esri.com/.

Lewis and Clark Across Missouri, http://lewisclark.geog.missouri.edu/index.shtml

USGS, EROS Data Center, http://edc.usgs.gov/geodata/