Geological Survey Bulletin 613 Guidebook of the Western United States: Part C. The Santa Fe Route

Leaving Wagon Mound the train passes across a narrow tongue of the lower lava flow and a short distance farther south crosses a wide valley from which there are excellent views of the high lava-capped mesas to the north. The high ridge known as the Turkey Mountains is a prominent feature west of Bond. (See sheet 12, p. 72.) It is due to a dome-shaped uplift of the rocks which in the center exposes an extensive area of red beds and underlying limestones of Carboniferous age. The light-gray foothills are the outcrop of the upturned edges of the Dakota sandstone.

SHEET No. 12 (click on image for an enlargement in a new window)

For some distance south of milepost 730 the Greenhorn limestone is near the track, and finally, as it is crossed by the railway, it is exposed extensively in cuts, notably between mileposts 732 and 734. A short distance beyond milepost 734 the route descends from the flat ridge of the limestone into a broad area of lava (basalt). This lava came from the Maxson Crater, an irregular volcanic cone which is visible on the southeast slope of the Turkey Mountain uplift, 5 miles west of Optimo (op'tee-mo). The lava flowed down slopes of Dakota sandstone, then across the broad flat which is now traversed by the railway from Optimo nearly to Shoemaker, and finally down the canyon of Mora River nearly to its mouth, 20 miles to the southeast. The flow is moderately recent and exhibits a variety of features characteristic of the later basalt flows. Its surface is considerably blistered, and much of the rock is vesicular or spongy, with small cavities due to the escape of steam.

In the broad valley south of Optimo the lava spread out widely, but in flowing down the deep canyon of Mora River it was narrowed to a few hundred yards. It filled this canyon about halfway up its sides, but the river has since cut a narrow inner gorge into the lava sheet and in places through the lava into underlying rocks, as shown in figure 10. This lava-filled canyon begins 6 miles east of the railway, and its outer walls of sandstone are plainly visible from the vicinity of milepost 740.

FIGURE 10.—Section across canyon of Mora River southeast of Optimo, N. Mex., showing relations of lava flow, looking east. The total depth of the canyon is about 700 feet.

Halfway between mileposts 741 and 742 the southern margin of the lava sheet abuts against a cliff of Dakota sandstone which extends northwestward. A short distance beyond this place, near Shoemaker, the bank of Mora River is reached, and the railway follows this stream along the north side of the deep canyon which it has cut in the Dakota sandstone and underlying beds. The beds lie nearly horizontal and in places the high cliffs of sandstone have at their bases the greenish-gray shale of the underlying Morrison formation. On the north side of the track at milepost 748 the Dakota sandstone is extensively quarried for railway ballast. Two miles beyond there is, on the south bank of the river, a bluff of Dakota sandstone, with Morrison shale¹ at its base.

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¹During the time of deposition of the clays constituting the Morrison formation there existed a great variety of remarkable reptiles of huge size. Restorations of some of them are shown in Plates X and XI (pp. 64, 65), based on bones exhumed from the formation in southern Colorado. These bones, which are in places abundant, are the remains of animals that were mired in the soft clay of which the Morrison formation largely consists. Some of these creatures, such as the Brontosaurus (Pl. XI, A), were 60 feet long. Many of them had remarkably small heads, notably the Stegosaurus (Pl. X, B), which had such a diminutive brain that it must have been very stupid. This animal was undoubtedly very clumsy also, but its huge size and protective armor aided in its preservation.

PLATE X.—A (top), ALLOSAURUS. A great carnivorous dinosaur or megalosaurian. Restored by Charles R. Knight from bones found in the Morrison formation, Colorado. B (bottom), STEGOSAURUS. A huge lizard that lived at the time of the deposition of the Morrison formation. Restoration by Charles R. Knight.

PLATE XI.—A (top), BRONTOSAURUS. A great amphibious dinosaur from horizon of Morrison formation, Wyoming. Restoration by Charles R. Knight. B (bottom), SKELETON OF DIADECTES. A reptile that lived in the Southwest at the time the red beds were deposited. From the Wichita formation (lower Permian) of Texas. Specimen in American Museum of Natural History, New York City.

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Watrous is the railway town for extensive cattle, sheep, and other interests. It dates back to the time of the Santa Fe Trail, the Cimarron branch of which passed through the western portion of the village. Eight miles north are the ruins of Fort Union, one of the most important military stations on the Santa Fe Trail, where the two principal branches of the trail from the north joined. The place may be seen far to the north from points a short distance beyond Watrous. The adobe houses are unroofed, most of the walls are falling into ruins, and the grounds are overgrown with grasses, but the visitor may see that the fort had accommodations for a large garrison. This fort served not only as a refuge for the settler and the traveler, but its storehouse and arsenal carried a large stock of Army supplies. Its possession was the strategic object in the Civil War in the far West. To its protection Union volunteers rushed over the snowy mountains from Denver, while Confederate troops marched a thousand miles from Texas to take it. Only the defeat of the Texas soldiers at Glorieta Pass prevented the Confederates from capturing the Army supplies and ammunition stored in Fort Union.

In the vicinity of Watrous there are wide alluvial flats that have long been utilized for farming, mainly by the assistance of irrigation from Mora River and a branch stream, Sapello Creek. The Mora drains a portion of the east slope of the Rocky Mountains. Gagings by the United States Geological Survey at La Cueva (kway'va), 15 miles above Watrous, found that its average flow was 29 second-feet in 1909 and 20.3 second-feet in 1910.

On the south side of the track three-fourths of a mile beyond Watrous is a large quarry for obtaining massive blocks of Dakota sandstone, which are used for making embankments along portions of the railway as a protection from washouts.

East of the railway at milepost 753 is a granite monument marking the location of the Santa Fe Trail from Fort Union to Las Vegas. Its course was very nearly the same as that now followed by the railway. A short distance beyond Kroenigs siding the upgrade of the railway carries it from the Dakota sandstone to the Graneros shale¹ and thence within 2 miles to the summit of an extensive plateau of Greenhorn limestone, above which to the west rise buttes of Carlile shale. This plateau is the divide between the drainage basin of Mississippi River and that of the Rio Grande. A fine vista of the Rocky Mountains is afforded toward the north and west; due west is Solitario Peak, a knob of granitic rocks rising to an altitude of 10,200 feet, and farther northwest are still higher peaks near the center of the range. The Turkey Mountains and Ocate Crater are conspicuous toward the northeast.

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¹A contact of these rocks is well exposed at a point half a mile west of Kroenigs siding. To the south and west of this place is a low ridge of the Greenhorn limestone, which overlies the Graneros shale. All the beds in this vicinity lie nearly level or dip at a low angle to the west.

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Onava is a small settlement sustained by irrigation with water brought through canals from streams and reservoirs a few miles to the northwest. From Onava southwestward the railway runs on a gentle down grade to Las Vegas, all the way on the surface of the Greenhorn limestone, except where it is covered by a thin capping of the Carlile shale. The bed dips gently to the west and southwest, so that the surface of the plateau is in greater part a dip slope of the limestone. This rock is exposed in many railway cuts, especially near Las Vegas, and to the west at varying distances is a line of buttes of the overlying Carlile shale. The relations of the rocks near Onava and along a line passing through Las Vegas are shown in figures 11 and 12.

FIGURE 11.—Section 6 miles north of Las Vegas, N. Mex., looking southwest. a, Carlile shale; b, Timpas limestone; c, Apishapa (?) and Pierre shales; d, Greenhorn limestone; e, Graneros shale; f, Dakota sandstone and Purgatoire formation; g, Morrison formation; h, red beds.

FIGURE 12—Section through Las Vegas, N. Mex., looking south. a, Carlile shale; b, Greenhorn limestone; c, Graneros shale; d, Dakota and Purgatoire sandstones; e, Morrison shale; f, massive sandstone, capped by thin limestone; g, red shales and sandstones; h, sandstone in middle of red beds; i, lower red beds; j, Magdalena limestone.

Las Vegas (vay'gas) is a railway division point where all the trains stop, most of them for meals at the Castañeda (cas-tahn-yay'da), a hotel named for the young soldier who accompanied Coronado's expedition and wrote the narrative of it. The Santa Fe Railway reached Las Vegas in 1879 but continued building rapidly to the south. The portion of Las Vegas near the railway is relatively modern; the "old town," or original Mexican settlement on the Santa Fe Trail, is some distance west of the station. The name is Spanish for the meadows. On the flat roof of a building in Las Vegas Gen. Kearney stood in 1846 to administer to the Mexican citizens the oath of allegiance to the United States. Five years before that the plaza of Las Vegas was the scene of a great celebration over the surrender of the various detachments of Texans who had entered New Mexico to induce the inhabitants to join the Texas Republic. Gallinas Creek, which flows through Las Vegas, is a small stream draining a portion of the east slope of the Rocky Mountains. Gagings by the United States Geological Survey have shown that its average flow is about 23 second-feet. The water is utilized for irrigation.

A branch railway goes northwestward from Las Vegas, 6 miles to the Montezuma Hot Springs in a gap in the foothills where there is a large hotel and sanitarium that, in recent years, has not been open.

Most of Las Vegas is built on the Greenhorn limestone, and this formation also crops out extensively in the high bluff just east of the railway station, where all its beds may be seen. At the base, near the stream, is the underlying Graneros shale, passing upward by a few feet of transition beds into the Greenhorn limestone. This limestone presents its usual characteristic features of an alternation of many thin beds of nearly pure limestone and dark shale. In some of the shale and in a few beds of the limestone there are abundant impressions of the characteristic fossil Inoceramus labiatus, a mollusk with oval shell somewhat similar to the oyster. The thickness of the Greenhorn limestone in these exposures is fully 100 feet, and the top of the formation constitutes a mesa extending some distance east to low hills of Carlile shale which rise above it.¹

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¹A short distance north of Las Vegas the Greenhorn limestone passes under the Carlile shale, a formation which carries numerous round concretions in its upper portion. This is overlain by a thick body of shale representing the Niobrara group and Pierre shale and occupying a basin which pitches to the north and the beds on the western edge of which are steeply upturned along the foothills. In these foothills a short distance west of Las Vegas, and especially in the canyon near the hot springs, are extensive outcrops of the succession of rocks underlying the Greenhorn limestone, comprising the Graneros shale, Dakota and associated sandstones, Morrison formation, "Red Beds" of Triassic and Carboniferous age, and older Carboniferous limestones, all standing nearly vertical on the east side of the great mass of granites and schists of the main Rocky Mountain uplift.

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A few miles east of Las Vegas the plateau or bench of the mountains on which it is situated terminates in a great vertical escarpment of Dakota sandstone, which overlies the Morrison formation. This escarpment overlooks the Canadian and Pecos valleys, which lie between the Las Vegas Plateau and the western edge of the Staked Plains of Texas.

At Las Vegas an extra engine is attached to haul the train up the heavy grades of the long climb over the south end of the main chain of the Rocky Mountains, which lies between Las Vegas and Lamy. In order to find suitable grades for crossing this range it was necessary to deflect the railway line far to the south, for in the country west and northwest of Las Vegas the lowest passes through the mountains are at altitudes greater than 10,000 feet, or more than 2,500 feet higher than Glorieta Pass, the one utilized.

On leaving Las Vegas, the train goes southward, at first over a rolling plain of the Graneros shale along Gallinas Creek (gahl-yee'nas; locally gah-yee'nas). Within 2 miles the base of this shale is reached, and the underlying Dakota sandstone appears in railway cuts and in the canyon a short distance east of the track. Half a mile beyond is a shallow basin of the shale, in which small outliers of the overlying Greenhorn limestone rise as hills on both sides of the track.

Just west of Romero (ro-may'ro) siding the railway turns west into a gap through a "hogback" ridge that constitutes one of the foothills of the mountains. This hogback consists of Dakota sandstone and associated rocks steeply upturned on the east side of the uplift of the main range of the Rocky Mountains. The ridge is caused by the hardness of the upturned beds, which resisted to some extent the elements that eroded to a lower level the soft overlying shale on the east and the red shales on the west. The hogback ridge extends far to the north along the foot of the mountains, but toward the south, where the dips become gentler, it finally merges into a plateau presenting steep cliffs to the west and south, which are visible east of the railway for several miles.

Beyond the hogback ridge the railway goes southward up a valley of red shale, but in places it bears westward through gaps in several small ridges caused by layers of sandstone included in the red shale. The manner in which these sandstones give rise to small ridges is an instructive illustration of the relation of hard and soft rocks to the topography. The hard layers vary in thickness, but all make ridges of greater or less prominence. To the west of the railway there rises out of the red shale valley a bed of hard sandstone of considerable thickness, which constitutes a high ridge extending for many miles north and south parallel to the hogback ridge. The relations of these rocks are shown in figure 13, a section across the railway in the vicinity of milepost 779, half a mile beyond Ojita siding. The Spanish word ojita (o-hee'ta) means little spring.

FIGURE 13.—Section across the east slope of the Rocky Mountain uplift near Ojita, 8 miles southwest of Las Vegas, N. Mex. a, Limestone of Magdalena group; b, thick, hard buff sandstone; c, beds of hard sandstone in red shale; d, Triassic sandstone; e, gray shale (Morrison); f, Purgatoire formation and Dakota sandstone.

The sandstone in the ridge west of the railway is thick and hard, and is a persistent member in the middle of the great succession of red beds throughout this region. It is crossed by the railway in a sharp turn to the west at milepost 785, at the bridge over Tecolote (tay-co lo'tay) Creek.

From this place westward the surface of the sandstone is traversed for some distance. On some of the higher mesas adjoining the track the overlying red shales remain.

At Chapelle there are long slopes of the hard sandstone. A mile beyond Chapelle the old Mexican plaza of Bernal (bare-nahl') is passed a short distance north of the railway. Near by, at Bernal Springs, the Colorado volunteers camped in 1862 before their successful battle with the Texans, who were fresh from victory over the Federal troops at Valverde and encouraged by their easy occupation of Albuquerque and Santa Fe. A mile south of Bernal rises the well-known landmark Starvation Hill, a butte capped by a thick mass of the hard sandstone above referred to. This butte was the refuge of a party of Spaniards pursued by Indians, and it is stated that they were kept on the hill until they finally starved to death. There is a cross on the top, erected by the Penitentes, of whom there are many among the Mexican residents of this region. The butte is an outlier of a high mesa to the south, which consists of a widely extended platform capped by the hard sandstone that extends along the railway east of Chapelle, here carried to considerable height by the upward rise of the strata. Owing to the hardness of the capping rock and the softness of the underlying red shale the mesa presents a very precipitous outward slope toward the north.

In passing along the foot of this mesa the railway is on the lower red beds for a short distance and then from milepost 792 to 794 on the still lower limestone of the Magdalena group,¹ of Pennsylvanian age which is exposed in many of the railway cuts.

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¹This limestone is a light-colored massive rock containing numerous impressions of marine shells and is brought up in a low arch along a prolongation of one of the axes of the main Rocky Mountain uplift. It is about 1,000 feet thick and is underlain directly by the old granites and schists which may be seen in the high ridges beginning 4 or 5 miles north of milepost 794. At this milepost the railroad is on the lower portion of the red beds again, and these continue for several miles west.

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Just beyond Ribera (ree-bay'ra) the railway crosses Rio Pecos (pay'cos), a large stream which rises in the south end of the Rocky Mountains, flows across eastern New Mexico and the western part of Texas, and finally empties into the Rio Grande. This is the first important stream of the Rio Grande drainage basin met in the westward journey, although Gallinas and Tecolote creeks, above referred to, are in the Pecos basin. According to gagings by the United States Geological Survey at Cowles, 20 miles or more to the north, the flow of this river averages about 100 second-feet. The water is used for irrigation at many places. There are many Mexican settlements along Rio Pecos. One of these, San Miguel (me-gale'), is a large plaza plainly visible from Ribera station, about a mile to the south, and another, San Jose (ho-say'), formerly an Indian village, is a short distance east of milepost 802. It was at San Jose that Gen. Kearney and the Army of the West encamped in 1846, expecting the next day to have a battle with 2,000 Mexicans under Gov. Armijo (ar-me'ho), who were reported to be waiting for them in the canyon beyond the summit. The following day near Pecos they learned that the Mexicans, after constructing elaborate breastworks, had quarreled among themselves, and the governor and his forces had discreetly retreated, leaving the way to Santa Fe open to the Americans.

It will be noted that most of the houses of the Mexican settlements are built of adobes (ah-doe'bays), which are large bricks made of sun-dried earth.² The roofs and in some houses also the framework are made of juniper posts, and the better houses are plastered. Houses of this sort are warm in winter and cool in summer.

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²In the West the term adobe is commonly used both for the material from which the bricks are made and for a house built of them.

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South of Sands and Fulton is a high plateau known as Glorieta Mesa, the northeastern foot of which is followed by the railway to Glorieta (glo-reeay'ta). This mesa presents toward the northeast a continuous line of cliffs, with level crest, surmounting long slopes which descend to the valley of the Pecos. The railway is built along this slope on an irregular shelf or series of shelves due to various sandstone beds in the lower part of the red bed series. Glorieta Mesa is capped by the gray to buff sandstone of the same bed which caps Starvation Hill and the mesa southwest of Chapelle.