KODELS CANYON FAULT, looking northwestward across canyon of same name. Base of Wingate cliff on left is just about opposite the top of the Wingate on right. Here, nature was kind to the geologist, for the vertical displacement (rise of left side with respect to right side) is virtually the thickness of the Wingate Sandstone—about 350 feet. The Wingate on the right is lighter colored than that on the left seemingly because rockfalls removed desert-varnish-coated rocks and exposed the true color of the sandstone. (Fig. 32)
GEOLOGIC STRUCTURES AT FRUITA ENTRANCE TO COLORADO NATIONAL MONUMENT. The stereoscopic pair of aerial photographs may be viewed without optical aids by those accustomed to this procedure, or by use of a simple double-lens stereoscope, such as the folding ones used by the armed forces during and after World War II. Geologic details may be identified by comparing photographs with the geologic map, figure 8. If viewer is unable to see stereoscopic pairs in three dimensions, looking at either photograph alone will convey a good idea of the geologic structure. The monocline near top of the photographs may be seen on the right-hand side of the highway in figure 43. Photographs taken in 1937 by U.S. Soil Conservation Service, hence, alinement of then unpaved Colorado Highway 340 differs from the paved present highway. (Fig. 33)
At this point in our story it might be well to point out that the folding and faulting of the rocks just described occurred when thousands of feet of younger rocks covered the area. Additional folding and faulting, drainage changes, and gradual removal of the overlying rocks occurred during the remainder of the Tertiary and Quaternary Periods, as will be discussed further.
Grand and Battlement Mesas, respectively east and northeast of the Monument, are capped by several resistant thick flows of dark basaltic lava. The molten rock welled up through fissures at the east end of Grand Mesa and flowed westward and northwestward over the eroded surface of Eocene rocks. Radiometric dating of a sample of the basalt indicated an age of 9½ million years plus or minus half a million years, placing the event in the Miocene Epoch of the Tertiary Period (fig. 61).
A small remnant of the lava on the crest of the Roan Cliffs just southwest of the present town of Grand Valley indicates that the flows crossed this part of the ancestral Colorado River Valley and may have pushed the young stream westward.
The lava flows are about 800 feet thick on the eastern part of Grand Mesa but are only about 200 feet thick above the western rim of the mesa. As the ancestral Gunnison River is believed to be pre-Miocene in age, it is not known whether or not the lava flows crossed the old river valley and reached as far west as the Monument.
During most of the Pliocene Epoch the ancestral Colorado River did not flow past what is now Grand Junction; instead, it joined with the ancestral Gunnison River about 10 miles southeast of the present city, and the combined streams flowed southwestward across the slowly rising Uncompahgre arch through what was later to be called Unaweep Canyon (fig. 36). Southwest of the canyon, near the site of the present town of Gateway, the ancestral Colorado River was joined by the combined flows of the ancestral San Miguel River and the previously diverted ancestral Dolores River, then it flowed northwestward to what is now the mainstem of the Colorado River.
I have attempted to show my ideas of this ancient drainage system as it may have existed in middle to late Pliocene time in figure 34. But the stage was set for more spectacular drainage changes to follow.
Rivers, like people, do not always choose their courses wisely. After a few million years of downcutting through the soft sedimentary rocks, mainly what is now called the Mancos Shale, the ancestral Colorado and Gunnison Rivers found themselves cutting through the hard Proterozoic rocks in a deep gorge athwart the slowly rising Uncompahgre arch, which greatly slowed the downcutting power of the combined streams. Note in figure 34A that while the mighty ancestral Colorado and Gunnison Rivers were in this frustrating predicament, a young upstart tributary began cutting northward from what is now the mouth of the Dolores River (fig. 34D). Although the combined main rivers could lower their channel only very slowly because of the hard rock in Unaweep Canyon, the tributary was able to cut downward and headward quite rapidly through the soft Mancos Shale. It eventually cut around the northwestward dipping Uncompahgre arch and headed southeastward toward the ancestral Colorado River near the present site of Palisade.
Then occurred an act of piracy that put to shame the mightiest exploits of Blackbeard and Captain Kidd. In latest Pliocene or earliest Pleistocene time additional uplift of the Uncompahgre arch, an unusually large flood, or both, caused the ancestral Colorado River to overflow its banks and spill across a low shale divide into the headwaters of the tributary. Some ponding may have preceded the spillover. With this enormously increased supply of water, the tributary cut down rapidly through the soft shale and captured the entire flow of the Colorado River, but the ancestral Gunnison River still flowed through Unaweep Canyon, as shown in figure 34B. Stream capture of this type is appropriately called “piracy.”
But the piracy had not ended. Note in figure 34B that the “new” river sent out several tributaries, one of which headed for and, with the aid of yet additional and greater uplift, soon captured the ancestral Gunnison River, as shown in figure 34C. This second act of piracy left Unaweep Canyon really “high and dry” except for small streams that carried off what little water the canyon received from local rain and snow. While these piracies were taking place, the Book Cliffs and the edge of Grand Mesa gradually retreated away from the valley because of erosion, and more of the Uncompahgre arch was uncovered.
The rising Uncompahgre arch, whose renewed uplifts in latest Pliocene or earliest Pleistocene times played such an important role in the ultimate abandonment of ancestral Unaweep Canyon, was asymmetric in that the crest was not in the middle but was near the southwest side. Although sharp, locally faulted monoclines are found on both sides of the arch, including the part within the Monument, in general, the northeastern flank has a rather gentle northeastward dip; whereas, the southwestern flank of the arch also is bordered by normal faults of considerable vertical displacement.[31] Thus, after abandonment, the minor drainage in Unaweep Canyon continued to flow northeastward from a new divide near the southwestern border, and ancestral West Creek began cutting northeastward toward the new divide. The drainage pattern depicted in figure 34C differs slightly from my earlier interpretation and results from additional fieldwork.[32]
PROBABLE DRAINAGE PATTERNS AND LAND FORMS NEAR THE MONUMENT AT FOUR SUCCESSIVE STAGES OF DEVELOPMENT. Solid drainage lines taken from the Moab and Grand Junction, Utah-Colorado, topographic maps of the Army Map Service; dashed drainage lines are my own ideas. A, just prior to piracy of ancestral Colorado River; B, after piracy of ancestral Colorado River and just prior to piracy of ancestral Gunnison River; C, abandonment of Unaweep Canyon after renewed uplift of Uncompahgre arch and piracy of ancestral Gunnison River; and D, present drainage pattern after additional uplift and piracy of East Creek. Modified from Lohman (1961, 1965a, 1965b). (Fig. 34)
At the time of abandonment, ancestral Unaweep Canyon was a V-shaped canyon resembling Glenwood Canyon just upstream from the city of Glenwood Springs, Colorado. The reasons for its change in shape and appearance to the beautiful U-shaped canyon we find today and the profound effect the abandonment of Unaweep Canyon had on the deepening of the Grand Valley and the canyons of the Monument will be brought out in the section “Canyon Cutting.”
Like the dinosaurs before them, a few of the Tertiary mammals were so long on brawn and short on brains that they evolved into grotesque monsters and overspecialized themselves into early extinction. Fortunately, however, most of the mammals evolved more slowly and moderately into the forms we find today.
One group—the anthropoid primates—began to think, so they developed their brains rather than their brawn, particularly the Tertiary ancestors of man. Few remains of these ancestors have been found in Tertiary rocks, but many more have been discovered in rocks of the next geologic period—the Quaternary. Thus, this period may properly be regarded as the age of man, for man then began to dominate the Earth for better or for worse.
The Quaternary—latest and shortest of the geologic periods—is divided into the Pleistocene and Holocene (recent) Epochs (fig. 61).
During the Pleistocene Epoch, all continents of the Northern Hemisphere and some of the Southern Hemisphere were partly covered at least four times by huge glaciers. Each glacial advance in Europe and North America was ended by a warmer interval during which the glaciers melted and retreated northward; then, vegetation and soil had time to become re-established. Thus, the Pleistocene has properly been called the ice age.
None of the continental glaciers reached the Monument or the Uncompahgre Plateau, or arch, but small alpine glaciers grew in the high Rocky Mountains to the east, sculpturing sharp-crested peaks and ridges and forming beautiful valleys and lakes. Many of the beautiful lakes on Grand Mesa were formed by glaciation, but some near the edges were formed by landslides.
The increased streamflow from the greater precipitation and from melting alpine glaciers in the Rockies, particularly during times of glacial retreat, helped the Colorado River cut through the rocks faster, thus assisting in the formation of Colorado National Monument as we see it today. The river carried thousands of cubic miles of sediment to the Gulf of California, including a lot of rock that once covered the Monument, and the river is still actively at work on this immense earthmoving project.
If the ancestral Colorado River carried sediment at about the same rate as the present river since the building of Hoover Dam, it may have carried about 3 cubic miles of sediment each century. Now most of the rock debris is being dumped into Lake Powell—the new reservoir behind Glen Canyon Dam. When this, Lake Mead, and other reservoirs ultimately become filled with sediment, the Gulf of California will again be the burial ground.
But other events during the Pleistocene also played a role in shaping the area. The Uncompahgre arch was again uplifted and deformed in the Pleistocene soon after the abandonment of Unaweep Canyon. This caused added tilting of the strata and more bending and breaking along some of the folds and faults in the Monument.
East Creek, which drains the northeastern half of Unaweep Canyon, was forced to change its course during the Pleistocene Epoch by another act of piracy. After capture of the Gunnison River by the newly routed Colorado River, East Creek joined the Gunnison by way of Cactus Park. Then, a tributary of North East Creek headed southward and captured East Creek, as shown in figure 34D.
When the Colorado River was diverted into its new course through the Grand Valley past the Monument, the stream channel seems to have been only about 600 to 800 feet higher than it is today, but the present divide in Unaweep Canyon is now about 2,500 feet higher than the channel. The difference of 1,700 to 1,900 feet was caused by the additional uplift of the Uncompahgre arch during the Pleistocene.
Thus, the Grand Valley and its tributary canyons, such as those of Colorado National Monument, were cut since the abandonment of Unaweep Canyon, probably mainly during the Quaternary Period. This suggests that the cutting of the Monument’s canyons began only about 2 million years ago, but that much of the canyon cutting occurred only a few hundred thousand years ago. Indeed, the canyons are still slowly being deepened, lengthened, and widened.
As you stand on any of the lookout points and gaze down into the canyons of the Monument, you may well wonder how such immense chasms could have been cut by such puny streams that are dry most of the time. The streams flow only for short periods after heavy thundershowers or after rapid melting of snow. If you are lucky enough to see them flow, you will notice that the water is red or brown because of the suspended mud, silt, and sand. If the flow is large, you may see or hear pebbles and cobbles rolling along the bed. Accordingly, the streams and their cutting tools are slowly deepening the channels. But, you may ask, how does this account for such wide, broad-bottomed, cliff-walled canyons? Such streams act mainly as storm sewers to carry off the rock debris formed by other types of erosion.
When cutting first began, the Monument’s canyons were narrow, steep, and V-shaped. When the top of the hard, dark Proterozoic rocks was reached, however, downcutting slowed just as it had earlier in Unaweep Canyon. While the streams were thus hung up, other erosional processes caused the cliff walls to recede away from the streams, forming broad, flat-bottomed, U-shaped canyons.
Recession of the cliffs away from the middle of the canyons probably was caused partly by undercutting of the soft Chinle Formation by wind and in places by streams. This allowed slabs of the overlying Wingate Sandstone and younger rocks to break off and fall into the canyons—eventually to break up and to be carted off as sand and mud by streams.
But other processes are probably the ones chiefly responsible for the present shape and width of the canyons. The summer sun heats the cliff faces until they are hot to the touch, but in the present desert climate of the Monument the rocks cool rapidly after sundown. Oftentimes the hot cliff faces are chilled rapidly by summer thundershowers. Repeated heating, cooling, wetting, and drying causes expansion and contraction of the rocks so that thin layers break off and fall. This process goes on slowly even in winter on sun-facing cliffs, but it does not occur on the cliffs that face away from the winter sun.
Even more important, perhaps, is the alternate freezing at night and thawing by day on sun-facing cliff faces during the winter. Water in cracks near the cliff faces alternately freezes and melts, gradually prying off slabs of rock. Canyon walls that are shaded from the sun most of the winter, however, stay cold or frozen much of the winter; hence, they are not subject to repeated heating and cooling or freezing and thawing. Thus, you will notice that because of talus accumulation many such canyon walls are sloping rather than vertical.
To illustrate the above conjectures concerning the cutting and shaping of the canyons, let us consider several canyons that trend in different directions. We have seen in figure 12 that the left side of northeastward trending Red Canyon is a nearly vertical cliff that faces the sun most of the winter; whereas, the right side, which is shaded most of the winter, slopes gently enough to be climbed at many places. The sides of Ute Canyon, which trends more nearly northward (fig. 52), slope about equally, as would be expected. However, the west arm of the Canyon, which trends slightly southeastward, has sides whose slopes differ markedly (fig. 35).
This brings us to the remarkable transformation of the original V-shape of Unaweep Canyon to the beautiful U-shape of the present canyon, which is shown in figure 36. The abandonment of Unaweep Canyon discussed earlier removed the gigantic storm sewer that for millions of years carried off the products of vigorous erosion of the canyon walls by the processes just described. Rock materials that now fall from the cliffs of the inner gorge in hard Proterozoic rocks and that fall from the overlying softer sedimentary rocks simply pile up at the foot of the cliffs to form a canyon equally as U-shaped as those cut by glaciers in the high mountains. Indeed, Unaweep Canyon has been mistaken for a glacial canyon by many, including some geologists.
FALLEN ROCK, in west arm of Ute Canyon below waterfall, from Fallen Rock Overlook. Note that the sun-facing left side of canyon, containing the fallen block of Wingate Sandstone, is a vertical cliff; whereas, the shaded right side can be readily climbed. The right side contains a trail near the middle of the picture, but it is hidden by vegetation. (Fig. 35)
UNAWEEP CANYON, looking southwest from rim of inner gorge cut in hard Proterozoic rocks, just to the right side of first cattle guard on Divide Road, near middle of sec. 16, T. 14S., R. 100 W., about 5 miles northeast of drainage divide shown in figure 34D. Drainage divide is just around the corner to the right of the most distant part of the canyon visible. Slope above vertical cliff on right consists of Chinle Formation, Wingate Sandstone, and flat crest of Entrada Sandstone (Kayenta Formation is absent). Paved road in canyon is Colorado Highway 141. (Fig. 36)
This ends the brief geologic story of Colorado National Monument, except for a peek into the future, a description of trips through and around the Monument, and a comparison with other Parks and Monuments on the Plateau. The temporary nature of lakes, rivers, and even mountains has been discussed—the Monument of today and the new course of the Colorado River are no exceptions.
The Colorado River did not solve its problems by abandoning its hard-rock course in Unaweep Canyon in favor of a soft-rock course through Ruby and Westwater Canyons—it just postponed them. The river has again cut down into its old nemesis—the hard Proterozoic rock—in Ruby Canyon just within the Colorado border, in Westwater Canyon in Utah, and the Gunnison River has reached the hard rock at its confluence with Dominguez Creek, not far above Whitewater, as shown in figure 34D. Thus, once again hard rock is slowing down old man river, and will slow him down for a long time to come. Someday, Westwater and Ruby Canyons will be deep gorges like Unaweep Canyon. Then it is quite possible that another young tributary may sneak around the Uncompahgre arch some miles northwest of these canyons and pirate the river into a new soft-rock course.
By this time, the Monument will have changed appearance considerably. Some of the canyons will have come together by eating away the ramparts that separated them—just as the two entrances of Monument Canyon have already done. But as the lower canyons thus eliminate themselves, the headwaters will bite deeper into Piñon Mesa, so perhaps the Monument will simply creep slowly southwestward. However, renewed uplift, more volcanos, changes in climate, or other events could alter the picture.
Still, if the geologic clock ran as fast as the ones we use, the picture of the Monument we see today would be on the screen only a small fraction of a split second. But the geologic clock ticks on, slowly but surely, and, someday, the Holocene Epoch in which we live will become just another brief chapter in the long geologic history of the Earth.
How to see the monument depends in large part on how long you can stay, but it depends also upon the direction you are travelling to or through Grand Junction and Fruita, and on the mode of transportation. Moreover, the Monument has four entrances—two main entrances from Fruita (West Entrance) and Grand Junction (East Entrance), and two subordinate entrances from the Glade Park area to the southwest.
Though by no means as well known as our large National Parks, Colorado National Monument is more readily accessible than many. It is on two transcontinental highways (U.S. 6 and 50), is the western terminus of U.S. 24, and is on nearly completed Interstate 70, one of the most scenic transcontinental Interstate Highways. Highway I-70 supersedes many stretches of U.S. 6, 24, and 50, but the latter are still used in parts of the Grand Valley and elsewhere. The Monument also is on the main line of the Denver and Rio Grande Western Railroad, which still maintains limited passenger service between Denver and Salt Lake City, but this service may eventually be terminated. Grand Junction’s Walker Field is served by several airlines, and both Grand Junction and Fruita are served by busses.
Many people driving through the Grand Valley for the first time are unaware of the Monument’s existence unless they happen to see it on a roadmap or see road signs pointing toward it, but unfortunately the signs are unevenly and poorly distributed. People entering Grand Junction from the east on U.S. 6 and 24 or from the southeast on U.S. 50 are apt to see one or more of the signs—particularly when crossing Grand Avenue on First or Fifth Streets. If they are heading westward and can devote at least half a day, they may drive to the East Entrance, follow Rim Rock Drive for 22 miles northwestward through the Monument, stop at some or most of the scenic overlooks and the Visitor Center, leave via the West Entrance, and proceed northwestward on U.S. 6 and 50 or better yet on I-70. However, as will be described below, longer stops are much more rewarding. Those driving eastward on I-70 may see the sign at the Fruita interchange pointing southward toward the Monument—and may take the above described quickie trip in reverse. Those heading northwestward on I-70, however, may not be aware of the Monument until they see the sign at the Fruita interchange; then, they may not have or take time to double back southeastward through the Monument. If they do drive southeastward through the Monument, however, they can return to Fruita following a very scenic northwesterly route through The Redlands on Broadway (Colo. Highway 340) and South Broadway, or they may take a paved shortcut from near the East Entrance to South Broadway via South Camp Road (p. 118). Drinking water and sanitary restrooms are available in the headquarters area in the campgrounds and picnic grounds and Visitor Center, and in the Devils Kitchen Picnic Area. Food is not available in the Monument, so those planning to remain all day should bring lunches.
I have conducted many groups through the Monument, always choosing to travel northwestward from Grand Junction through The Redlands, just northeast of the Monument, to the West Entrance, then returning southeastward through the Monument.[33] On most days, taking the trip in these directions affords good lighting for photographing most of the scenic features. This and other routes are described in the next section and are plainly labeled so that the visitor may start with any trip he or she chooses. Regardless of how long you stay or which routes you follow, it is advisable to be well supplied with color film.
Some of the view points and overlooks have displays or signs to help interpret the scenic features, and more of these aids are added from time to time.
There are three maps in this report (figs. 3, 8, 26); these maps will be helpful to anyone touring the Monument. Figure 3 shows streams, highways and roads, principal trails, named features, overlooks, and trip-guide locations; figure 8 is a geologic map; and figure 26 shows localities where most of the photographs were taken. In addition, topographic maps of the Monument and adjacent areas by the U.S. Geological Survey, scale 1:24,000, are available from several sources and are a considerable aid to visitors. In addition to cultural and drainage features, such maps show the exact shape of the land by means of contour lines, which are level lines that go in and out of canyons, around ridges, and so forth. A special map of the Colorado National Monument quadrangle is available also in a shaded relief edition, which gives a three dimensional effect by proper shading of canyons and ridges. Both types of maps are for sale at the Visitor Center, and these and adjacent quadrangles, such as the Grand Junction, Fruita, Glade Park, and Island Mesa, are sold at several engineering and stationery stores in Grand Junction and at the U.S. Geological Survey’s Map Distribution Office, Building 41, Federal Center, Denver, Colorado, 80225. The latter office and the Visitor Center also sell copies of my “Geologic Map of the Grand Junction area, Colorado,” published in 1963 as Miscellaneous Investigations Map I-404.
1
We will begin our trip in the southwestern part of Grand Junction at the intersection of First Street and Grand Avenue, (this is also the intersection of U.S. Highways 6 and 50 and Colorado Highway 340), by following a sign on Highway 340 pointing westward toward the Monument. After crossing a viaduct over the railroad yards and a bridge across the Colorado River, we come to a traffic light and a sign pointing left toward the Monument. The road to the left connects with Monument Road which leads up No Thoroughfare Canyon to the East Entrance. However, we will continue westward toward The Redlands.
2
Just beyond the stoplight we cross a bridge over the Redlands Power Canal which carries 675 cubic feet per second (cfs, or ft³s⁻¹)[35] from the Redlands Diversion Dam on the Gunnison River about 2½ miles south of Grand Junction. A quarter of a mile northwest of the bridge, most of the water falls to a lower powerplant that generates electricity for pumping the remaining 50 cfs to three lift canals, which are used mainly for irrigating peach orchards in the eastern part of The Redlands.
3
After Colorado Highway 340 curves right it is known as Broadway—a paved road serving much of The Redlands and connecting with the West Entrance of the Monument. We will follow Broadway about 3 miles, passing low outcrops and roadcuts of the Dakota Sandstone, some of which contain coal beds and some of which are covered by a veneer of gravel laid down by the river when the channel was higher. Then, at the first store and filling station we turn southwest on another paved road known as South Broadway.
4
Just around the curve to the right is a T-intersection from which paved South Camp Road leads south to a growing suburban area; and 2½ miles to the southeast it connects with Monument Road at a point only half a mile north of the East Entrance of the Monument.
Excellent views of the cliffs of dark Proterozoic rocks, the overlying cliffs of the Wingate Sandstone, and the Redlands fault along the northeastern border of the Monument are seen all along South Broadway, but views from South Camp Road and several connecting roads to the southwest are especially good. (See figs. 37 and 38.) As noted earlier, the Redlands fault has a maximum vertical displacement of 700 or 800 feet, but dies out in scissors fashion at each end.
REDLANDS FAULT, looking west from South Camp Road about one mile south of South Broadway. Fault here is nearly vertical and normal, and lies between updragged Wingate Sandstone and dark Proterozoic schist, gneiss, and granite. All or most of the soft Chinle Formation has been squeezed out along the fault. Note smooth erosion surface atop hard, dark rocks surmounted by slope of red Chinle Formation and cliffs of Wingate Sandstone capped by lowermost resistant beds of Kayenta Formation. (Fig. 37)
5
As we continue westward on South Broadway, note on the right the brightly colored mudstone and siltstone of the Brushy Basin Member of the Morrison Formation strewn with large blocks of rusty-looking sandstone from the Burro Canyon Formation, which caps the high ridge on the right. Just above the deep cut on the right four-tenths of a mile west of the intersection with South Camp Road is a bronze plaque set in a masonry monument, whose lettering is easily readable in figure 39. Many years after the excavation in 1900 (fig. 22), Elmer Riggs contacted Al Look, of Grand Junction, in regard to the casting and erection of this plaque. Al, Elmer, Ed Faber, and a few other citizens put up the necessary funds and personally erected the plaque and monument. Somehow or other, Brachiosaurus was misspelled Brachyosaurus, as shown in figure 39, but the intentions were good. Later I will call attention to another similar monument commemorating the finding by Riggs of another dinosaur skeleton.
CLOSEUP OF UPDRAGGED WINGATE SANDSTONE ALONG REDLANDS FAULT, looking northwest from side road 1½ miles southwest of intersection of South Camp Road and South Broadway. White “pimple” atop cliff near left skyline is Liberty Cap, an erosional remnant of the Wingate Sandstone, reachable via the Liberty Cap Trail (fig. 3; and p. 108). Chinle Formation here was largely squeezed out along the fault. (Fig. 38)
After a sharp turn to the north and another to the west, South Broadway reaches the top of a hill just above the Elk’s Club and curves gently to the right past sandstone lenses in the Salt Wash Member of the Morrison Formation. A 610-foot-deep well at the house on the left formerly flowed about 1½ gallons a minute from the Entrada and Wingate Sandstones.
BRONZE PLAQUE AND MONUMENT MARKING THE DISCOVERY OF BRACHIOSAURUS ALTITHORAX RIGGS, above roadcut on South Broadway four-tenths of a mile west of South Camp Road. See also figure 22. For discrepancy in spelling text. (Fig. 39)
6
Half a mile to the north, South Broadway turns sharply to the left even though another paved road continues northward. Three-fourths of a mile to the west, we turn northwestward parallel to the Monument boundary fence for seven-tenths of a mile before turning north again. The 7-foot chain-link fence just to the left of the road is the northeastern boundary of the Monument and encloses the herd of buffalo. In the late forties or early fifties a young bull challenged the older leader for possession of the herd and gored and pounded the old bull so badly he had to be shot by a ranger. During the furious battle 125 feet of this strong steel fence was utterly demolished. It is reported that sometimes an old bull simply takes one look at the young challenger and retreats without a battle, but other lone or rogue bulls may temporarily or permanently leave the herd for other reasons. Such outcasts are dangerous and unpredictable. One bull kept a ranger “treed” for 4 hours on a steep rock ledge in the broiling sun before moving on to a patch of grass. Four of these critters delayed by one week my walking out a stretch of the Redlands fault on their side of the fence. I decided that a live geologist had advantages over a dead hero.
7
Throughout most of its 6-mile length the Redlands fault is a vertical or nearly vertical normal fault, but along and near this 0.7-mile stretch it is a reverse fault that dips from 45° to 60° to the southwest, as shown in figure 40 and in the cross section of figure 8. Good views of the fault are seen all along the fence, but especially at points one-tenth and four-tenths of a mile northwest of the first turn, the second of which is shown in figure 40. Just after turning north on South Broadway, let us turn west a few hundred feet on paved Wingate Drive to see the northwest end of the Redlands fault, which passes through a col to the left of updragged remnants of the thinned red Chinle Formation and the Wingate Sandstone, as shown in figure 41.
REVERSE PART OF REDLANDS FAULT, looking N. 65° W. from point on South Broadway along boundary fence. Most of Chinle Formation has been squeezed out, but lower part of Wingate Sandstone may be seen dipping about 45° southwestward beneath dark Proterozoic rocks. Next pink band to right is Entrada Sandstone. Jumbled mass of white sandstone slabs at right of photograph is part of Salt Wash Member of Morrison Formation and is known locally as “White Rock”. (Fig. 40)
NORTHWEST END OF REDLANDS FAULT, passing through col to left of updragged remnants of Chinle Formation and Wingate Sandstone. Fault, which here is normal, ends against unbroken Lizard Canyon monocline in next canyon to northwest. Looking west from point just south of Wingate Drive a few hundred feet west of South Broadway. (Fig. 41)
About half a mile north of the last turn, South Broadway rejoins Broadway (Colo. Highway 340) at a stop sign. After we turn left on Broadway and reach the first curve, we get a nice view westward into Monument Canyon, as shown in figure 42. The Park Service hopes to establish a new trailhead at the bridge one-tenth of a mile west of the curve, from which a new section of trail will follow the normally dry wash southwestward to join the old Monument Canyon Trail. After we cross the creek leaving the canyon, we pass a low hill of the Salt Wash Member of the Morrison Formation on the left. Just beyond the hill, the dirt road leading southwest to a farmhouse formerly was the beginning of the Monument Canyon Trail (fig. 3). There is a new temporary trailhead a quarter of a mile north, but it is hoped that a permanent one can be built at the bridge about a quarter of a mile to the southeast, as noted above. Hikers may see buffalo along this trail and should watch out for outcast bulls.
LOOKING WEST INTO MONUMENT CANYON, from curve on Broadway just northwest of end of South Broadway, showing Independence Monument. This monument was seen in figure 6 and will be seen again in figure 51. Redlands fault ends in this canyon; Lizard Canyon monocline can be seen on extreme right. (Fig. 42)
8
About half a mile north of the farm road we reach the highest point on Broadway (Colo. 340) at a drainage divide. Inasmuch as the three Redlands Lift Canals end east of the divide, there is quite a contrast between the lush irrigated lands east of the divide and the nearly barren desert to the west, a view of which is shown in figure 43. To the southwest of the divide is an excellent view of the northeastward-dipping beds on the Lizard Canyon monocline. On the left about a mile northwest of the divide we pass the other entrance of Monument Canyon, then Lizard Canyon, and a switchback on Rim Rock Drive ascending the ridge between Lizard and Fruita Canyons. The water well beneath elevated tank on left is 650 feet deep and formerly flowed at about half a gallon a minute from the Wingate Sandstone. Household needs are obtained by pumping.
LOOKING WEST FROM DIVIDE ON BROADWAY 2 MILES EAST OF WEST ENTRANCE TO MONUMENT. Monoclinal hill on right is Brushy Basin Member of Morrison Formation capped by basal beds of Burro Canyon Formation. Rocks at left middle are blocks of sandstone in the Salt Wash Member of the Morrison. (Fig. 43)
At the next intersection, Colorado Highway 340 turns right and continues about 2½ miles to Fruita; the highway to the left reaches the West Entrance of the Monument in a quarter of a mile. Before turning left into the Monument, however, we will interrupt our description of the trip by making a new start from Fruita for the benefit of people travelling from this direction.