Prior to the deposition of these Algonkian strata, the Laurentian rocks (the granite) upon which they rest were subject to a long period of "planation,"--as the grinding down and leveling of rock surfaces is termed.

After this planation was complete, a subsidence occurred; the whole area became the bed of an inland sea, and upon the planed-down granite, the debris that formed the Algonkian strata was washed.

While they were being deposited, the whole region was the scene of several seismic and volcanic disturbances, for great d.y.k.es and "chimneys" of lava are found, showing clearly that, by some means or other, the strata were broken and shattered, cracked and seamed, and that through these cracks the molten lava oozed--forced up from the interior of the earth. It spread out over the Algonkian rocks in small sheets or blankets, which here and there are still to be found to-day.

Tilting of the Algonkian Strata. Slowly this twelve thousand feet of strata emerged into the sunlight. In the uplifting processes, the surface of the earth, where they were, became tilted, and these strata therefore "dipped"

or "tilted" away from the perpendicular. As they emerged, weathering and erosion began. It is most probable that this process of degradation began and continued while the topmost strata were at or near sea level, so that it was a simultaneous process with the uplift.

Erosion of the Algonkian. How many centuries this weathering and washing away process consumed no one knows. At the close of this epoch, however, the Algonkian strata had been eroded almost away, owing to its tilted condition, so that in some places even the surface of the Archaean was exposed, and suffered the planing-down process. Figure 1 on plate facing page 98 is a suggestion as to the possible appearance of the rocks at this time.

Even then, in those far-away, early ages of history, if one had been present to measure these strata, he would have discovered the astounding fact that, although he had measured them and found twelve thousand feet before they began to emerge from the ocean, there were but about five hundred feet of them left. This is one of the interesting facts in geology,--that an observant reader can deduce so much from so little.

The twelve thousand feet deposit. "But," asks the layman, "I cannot possibly see how, if only five hundred feet of strata are left, any one could ever tell that there were once twelve thousand feet. If eleven thousand five hundred feet are gone, how do you know they ever existed?"

A very reasonable question and one very easily answered. Refer to the sketch. Let the bracket on the right show the present width of the remaining strata, viz: five hundred feet. Now observe the tilted condition of the remnants. To get the original height of the depositions begin with No. 1, the stratum nearest the Archaean and measure that. Suppose it gives us five hundred feet. No. 2 gives two hundred feet; No. 3, five hundred feet; No. 4, one hundred and seventy-five; and so on up to No. 14. As these strata were deposited horizontally, all we have to do is to mentally replace them in their horizontal position. Throw the tilted strata back again into their original condition, and by this method of measurement it is seen that the twelve thousand feet can be made up. Figure 2, facing page 98.

Another interesting question here arises: "What became of the vast quant.i.ty of sand and silt and pebbles that formed and were carried away during such a gigantic process? For, think of it, eleven thousand five hundred feet of strata, or rock, two miles high, almost three times as high a ma.s.s as the present distance in vertical height from El Tovar to the river! Where has it all gone?"

Naturally an answer to these questions is mere conjecture, as only from a study of the facts revealed underneath the present strata, can any comparative knowledge be gained of the conditions existent at that prehistoric age. There may have been one river, or a score, or any number between, and it is probable one or more rivers carried the Algonkian debris westward and deposited it, as the Colorado River (not brought into existence until centuries later) is now doing with the debris of the existent strata.

Another Subsidence. Now, a new era is about to dawn. Planed and smoothed off as they are, the Algonkian and Archaean ma.s.ses are to be submerged once more in the ever receptive ocean. A period of subsidence occurs, and the whole area is soon hidden under the face of the sea. But, all around these are ma.s.ses, some day to be mountain peaks, that refuse to sink again into the sea. Then the forces of the air a.s.sail them. If they cannot be drowned, they shall be gnawed at, smitten, cut and worried by the air, the chemicals of the atmosphere, the storms, the rain, the hail, the frost, the snow, and thus made to feel their insignificance. Slowly or rapidly, they yielded to this disintegrating process, and as the rocky ma.s.ses broke up, they were washed by the rills and streams into the bed of the sea, where they soon rested upon the tilted ends of the Algonkian strata and exposed surfaces of the Archaean ma.s.ses, waiting for them.

The Deposition of the Tonto Sandstones. The wise men tell us that this ocean was a salt sea, and that it was quite shallow while these new sediments were being deposited. Little by little one thousand feet of the sediments of this epoch were washed down, so that it is very likely that the tilted strata upon which they rested slowly sank lower and lower to accommodate them. Then, for some reason or other, there was a rest for a while--a few hundreds or thousands of years--and the ma.s.ses of sediments became cemented into sandstone and shale, which we call the Cambrian formation, or the Tonto sandstone. This is to be seen resting both upon the Archaean and Algonkian from the porches of El Tovar. It is composed of strata of dull buff, very different from the brilliant reds--almost crimsons--of the Algonkian, and the bright reds of the strata which later were to rest above them.

Geological Terms. What an audacious science this geology is! How ruthlessly it wrests aside the curtain from the mystery of the past, and how glibly it deals with thousands, millions of years, tying them up into packages, as it were, and handing them out labeled "eras" and "periods." As usual, the names made by the wise men are hard to p.r.o.nounce, and seemingly hard to understand. But a few minutes will take away the difficulty. They divide the eras into four, viz.: 1, Proterozoic; 2, Paleozoic; 3, Mesozoic; 4, Cenozoic. All these "zoics" have to do with life. Proterozoic means before life, and signifies the rocks that contain no fossils indicative of life; Paleozoic signifies the most ancient forms of life; Mesozoic signifies "middle life" or those between the most ancient and the Cenozoic, or recent forms of life. The periods are lesser divisions of the eras. In the Proterozoic, there are two periods, viz.: the Archaean and the Algonkian.

The Paleozoic has six periods, viz.: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. The Mesozoic era has three periods, the Tria.s.sic, Jura.s.sic and Cretaceous, while the Cenozoic era names five periods,--the Eocene, Oligocene, Miocene, Pliocene and Pleistocene.

Absence of Certain Strata. To shorten our story, let me at once say that during the periods that the Ordovician, the Silurian and the Devonian were forming, the Grand Canyon region was either above water so that it received none of these sediments, or, if any were deposited, they were almost entirely removed by the weathering processes before described, ere the region again sank into the ocean to receive the deposits of the Carboniferous epoch.

The Carboniferous. During this latter period, more than three thousand feet of strata were deposited. These are the most striking in appearance of all the Canyon strata, for they reach from the Tonto shales to the rim, and consist of three princ.i.p.al strata (with many smaller ones in between). The largest is the red-wall limestone, which const.i.tutes the base of nearly all the architectural forms found in the Canyon, and is the thickest of all the strata. It presents the "tallest" wall of the series. The two separate walls, one above the other, on the top of the Canyon, as seen in the arms of the amphitheatre at El Tovar, are the other two wide members of this Carboniferous period. The lower is the cross-bedded sandstone, and the upper the cherty limestone. There is a remarkable difference in the appearance and the material of which these Carboniferous strata are formed, and those of the East and Europe. We generally think of coal-beds--carbon when this period is mentioned. Here there are none. In the East, in England, and in other parts of Europe, vast marshes existed in this period, and the rank vegetation of these marshy areas formed the coal-beds, with which the Carboniferous there abounds. It is only by the fossils found that the periods to which the various strata belong are determined, and the fossils, millions of which abound in the upper limestone, are clearly of the Carboniferous epoch.

As these strata and this period bring us to the "rim" of the Canyon, it might be easy to imagine that the processes of uplift and subsidence, and deposition of more strata, as far as the Canyon region is concerned, now cease. Such, however, is not the case.

Later Strata. As we go away from the Canyon, either north or east, we find thousands of feet more of the later depositions, and the geologists affirm that many of these at one time may have overlaid the Canyon region. There is circ.u.mstantial evidence, amounting almost to proof, and Figure 3 of plate facing page 99 suggests what that evidence is. It should be carefully noted that the Canyon has been cut through the highest portions of a ridge, which runs generally from east to west, and the slopes of which, therefore; were north and south from the ridge. As one travels north from the Canyon, he finds all the way along, for hundreds of miles, that he goes on a down slope for a number of miles and then suddenly comes to the jutting edges of slightly tilted strata (only 2 degrees) which make a cliff up which he must climb. Arrived at the top of this, the downward descent begins again, until another ridge of these slightly tilted strata appears, see Figure 3 of plate facing page 99. Thus he continues up into Utah, and south and east into Arizona.

Now, in imagination, restore these cliffs of Permian, Tria.s.sic, Jura.s.sic and even Cretaceous strata over the whole Canyon platform. Figure 4 of plate facing page 99.

Red b.u.t.te, which is the prominent landmark seen from the railway on the right, when going from Williams to the Canyon, is said to be a remnant of the Permian.

Deposition of Strata in Shallow Water. It is, I believe, generally accepted by the geologists that the acc.u.mulation of much of the sediments of the Cambrian, Carboniferous, Permian, Tria.s.sic, Jura.s.sic and Cretaceous periods took place in shallow water, and that the sea bottom slowly sank under the weight of the increasing deposits. Hundreds, thousands of years must have elapsed during the process, for the indications are that the sinking did not exceed a few inches every hundred years! As carefully measured, these sediments then amounted to about two miles. Imagine, then, these Cambrian rocks, that at El Tovar are clearly seen above the "granite" or Archaean, sunk in the ocean, to the depth of two miles, and covered over with the various strata, the topmost of which was barely above sea level at periods of low tide.

Cretaceous Uplift. Then began another epoch of uplift. Slowly the Cretaceous rocks emerged from the sea, and were subject to the fierce attacks of nature that produce erosion. Now we have to grope blindly for a while, as the wise ones do not have facts enough upon which to speak with definite certainty. But it is a.s.sumed that a great warping of the earth's crust took place, and that in this revolution some of the plateau sank,--supposedly the northern part, though it certainly extended across the Canyon nearly as far south as Williams and Ash Fork, and other parts--the edges--arose, and thus formed a basin which became another vast inland sea.

Eocene Lake. We know this was an inland sea, and had no connection with the ocean, for all the fossils and sediments deposited in it reveal that they are fresh-water organisms. In this sea, as in the earlier oceans, vast deposits of sediment were made in the early Eocene period, and another period of subsidence occurred. Then the great lake was drained, and the uplift began, slow and sure; then, and not before, were the conditions existent that have made the Canyon country as we see it to-day. Peaks and islets received the rainfall, tiny rivers were formed that grew larger and cut their way in deeper, as the uplift continued. The princ.i.p.al stream, which was then born, was the Colorado. It is supposed, from various evidences, that the rainfall was very much more abundant then than now, and consequently the rivers had greater flow, and more eroding and carrying capacity. The uplift continued, and the geologists tell us it did not cease until about fifteen thousand feet, deposited since Cretaceous times, were thrust up into the air. As almost all this ma.s.s of deposition has disappeared from the immediate Canyon region, we are compelled to believe that it has been swept away down the Colorado River to join the sands of the Carboniferous and later periods in the Colorado Desert, the Salton Basin, the great low region of Lower California, and the Gulf itself.

Less by Erosion in the Canyon Region. Now figure out for a few moments the results of these different erosive periods. Eleven thousand five hundred feet of Algonkian gone; a small amount of erosion in the Cambrian epoch, the depth of which is unknown; and then the great denudation of the Eocene period sweeping away upwards of fifteen thousand feet of strata, give us a total of twenty-six thousand five hundred feet that have totally disappeared from the Canyon region. A vertical mile is five thousand two hundred and eighty feet. Mount Washington is about six thousand five hundred feet above the sea,--a trifle higher than Mount Lowe, near Pasadena, California. Take off from this six thousand five hundred feet, say one thousand five hundred feet, for the level of the country at the base of these two mountains, and then imagine a region five times as high as both of them, covering an area of country of possibly thirteen thousand to fifteen thousand square miles, slowly planed off by the erosive forces of nature.

Formation of River Beds. How was it done? I have spoken of the peaks and islets that first emerged from the Eocene Sea, and received the rains. Down their slopes ran the earliest watercourses, first as rills, then as creeks, finally as rivers. The higher the peaks ascended, the more the accompanying land was lifted up, and therefore the longer and deeper became the rivers.

The course of a river once established, it is exceedingly difficult to change it--hence the law that geologists call "the persistence of rivers."

By and by, the uplifted country appeared as one vast area of river valleys, separated by stretches of plateau. Little by little, working by laws that are pretty well understood, the swift flowing avers cut downwards. When their velocity ceased, the widening of the river courses began, and progressed with greater rapidity, so that, in time, the divides that intervened between the rivers were worn away,--a process rudely shown in Fig. 5 A. B. C. and D. of plate on page 110.

The Formation of the Canyon. Now, in imagination, let us hark back to the day when this plateau was in the condition thus described. Nearly everything in the way of strata has been planed down to the Carboniferous rocks. The plateau is about at sea level. One great river already exists, with two arms, now called the Green and the Grand, the main river some day to be known as the Colorado. Slowly the uplift begins. It is a fairly even process, and yet there is slightly more pressure brought to bear under the southern portion, so that the whole ma.s.s has a slight tilt to the north.

Professor Salisbury found certain beds of rock at seven thousand eight hundred feet above sea level at the base of the San Francisco Mountains near Flagstaff. Forty-five miles north, at the Grand Canyon, these same beds are only six thousand four hundred feet above sea level, while at the Vermilion Cliffs, another forty-five miles to the north, they are but four thousand four hundred feet above the sea.

Yet in spite of this northward tilt, when the eye ranges over the country to the south and west, from the upper porch of El Tovar, a large area of depression can clearly be seen, showing that surface erosion has planed away much of the upper crust.

The Plateau Region. Now we are ready to take a look at the borders of the plateau region. On the north, it extends into Utah, where still higher plateaus bound it. To the west, it extends by gigantic steps into the desert region. The main step is along the Grand Wash, near the one hundred and fourteenth meridian. To the south, there is one glorious step, known as the Mogollon Escarpment (locally the Red Rock Country), some three thousand feet high, which extends for a number of miles east and west, and then breaks down. This step and broken levels lead to the irregular lands of Central and Southern Arizona. On the east, the plateau extends to the Echo Cliffs beyond Marble Canyon, and as far as the ridge of the Continental Divide, where the Santa Fe crosses the Zuni Mountains, east of Gallup, N.

M.

Present Conditions. With this general view of the great plateau in our mind's eye, we are prepared to examine present conditions at any given spot in the Canyon. Let us, therefore, take a seat at El Tovar, and try to read a few pages of the stone book of Creation as opened there. Suppose all this vast region at about sea level, and the uplift just beginning. The course of the Colorado River is already well defined. As the uplift continues, the cherty limestone and possibly the cross-bedded sandstone are both cut through, as the plateau slowly emerges. Whether the process of uplift is slow or rapid, as soon as a stratum emerges, it becomes subject to the influences of weathering, and the uppermost strata appearing first, they are weathered most. Hence the recession of the uppermost cliffs is greater than that of the cliffs lower down. The differences in hardness and resistance to weathering are alone responsible for the step-like profile of cliffs and terraces. The lower platform owes its width entirely to the rapid weathering and recession of the soft shales, which overlie the Tonto sandstones. The red-wall limestone, on the other hand, remains standing out as a cliff because of its exceeding durability.

The Faults. During the final uplift, the river cut through the Cambrian and Algonkian strata, and into the Granite Gorge as we find it to-day, and the process is still slowly going on. During these various periods of uplift, there were other changes occurring. Sometimes the uplift was uneven, certain parts of the plateau being lifted more rapidly than other parts; then occurred breaks in the strata, called faults. There are a great number of these faults in the plateau country, most of them crossing the Canyon from north to south. This faulting, as is readily seen, would produce cracks, and as the uneven uplift continued; the strata on one side of the crack would be lifted higher than the strata on the other side. Or, the strata on one side of the crack would be uplifted, while the other would subside.

Bright Angel Fault. El Tovar rests directly upon the strata affected by the Bright Angel Fault line. On going down the Bright Angel Trail, one cannot fail to see, as he pa.s.ses the tap of the cross-bedded sandstone, the break in the strata. To the left it is fully one hundred and fifty to two hundred feet higher than it is on the right. The same depression may be observed in driving out to Hopi, Point, or returning. The stratum on which the road is made should be at the same level as the stratum on which El Tovar rests.

Fault at Ba.s.s Camp. This fault is but one of a score or more on the plateau. At Ba.s.s Camp there was a fault which displaced the strata on each side of the "break" to the extent of four thousand feet. Later, another fault occurred, which readjusted the displacement somewhat, and reduced the difference to two thousand feet, yet left the evidences of the former wide divergence. It was also during these uplift periods that the volcanic mountains of the region came into existence, as the San Francisco Range, Mounts Kendricks, Sitgreaves, Williams and Floyd on the south, and the Uinkarets--Mounts Trumbull, Logan, Emma--on the north.

Lava Flows. In one place, south of Mount Emma, Powell's party saw where vast floods of lava had flowed from it into the river. They declare that "a stream of molten rock has run up the Canyon three or four miles, and down, we know not how far. The whole north side, as far as we can see, is lined with the black basalt, and high up on the opposite wall are patches of the same material, resting on the benches, and filling old alcoves and caves, and giving to the wall a spotted appearance." All these volcanic mountains can be seen from Hopi or Yavapai points, near El Tovar.

The Algonkian Strata. The Algonkian strata of the Grand Canyon are by far the most interesting; Major Powell was the first to call attention to their existence in his report of explorations of 1869-1872, and he discusses their origin and history as far as was possible with the small amount of data he had at hand. Later Dr. Charles D. Walcott, his successor as Director of the United States Geological Survey, and now the Secretary of the Smithsonian Inst.i.tution, spent a full winter in the heart of the Canyon, especially studying the unique formations. Unique they are, for, though found elsewhere on the earth, they are exceedingly rare, and, up to this time; had received little study and were unknown and unnamed. The area studied by Walcott lies at the very entrance to the Grand Canyon, near where the Marble Canyon and Little Colorado Canyon join the main one. While the series cross the river and are a fine feature of Red Canyon Trail, the main study was done on the north side. Dr. Walcott thus locates the site of his studies: "This area, between 35 degrees 57 minutes and 36 degrees 17 minutes north lat.i.tude, and between 111 degrees 47 minutes and 112 degrees west longitude, is in the valley portion of the Canyon, between the mouth of Marble Canyon and a point south of Vishnu's Temple, a little west of where the Colorado River changes its course from south to southwest. It is wholly within the greater depths of the Grand Canyon, east and southeast of the Kaibab Plateau. The intercanyon valleys of this portion of the Grand Canyon extend back from three to seven miles west of the river, and are eroded in the crest of the Monoclinal fold that forms the eastern margin of the Kaibab Plateau."

There are also interesting remnants of Algonkian directly opposite El Tovar to the west of the Bright Angel Creek. They are easily discernible by their brilliant geranium or vermilion color. They extend for a mile or more westward, and rise above the Tonto sandstones, which properly belong above them.

The most remarkable deposit and exhibition of Algonkian strata in the Canyon, so far as known, occurs directly east of the great Kaibab Plateau, opposite the Little Colorado River. Here there must be several, possibly five or six thousand feet of these interesting strata, which Nature has allowed to remain up to our day. Geologists are now investigating them more thoroughly than ever before, and we may expect, when they publish the reports of their labors, that our geological knowledge of the Algonkian epoch, and possibly of other puzzling matters, will be much increased by the light they will throw upon them.

CHAPTER XIV. The Canyon--Above And Below

The Canyon Rim. There are several rather remarkable and surprising points of difference between the Canyon on the rim, and the Canyon in its depths.

Above, the whole Canyon region, save during the rainy season, is waterless, and while not barren, owing to the growths made possible by winters' snows and summers' rains, it is a veritable desert as far as water, whether in streams, creeks, rivulets or springs, is concerned.

Drainage of the Canyon. On both sides of the Canyon, all the surface water of the rains drains away from the Canyon for miles, and not until it has flowed, perhaps from within a few feet of the edge of the abyss itself, from twenty to a hundred miles, does it empty into the drainage channels which, burrowing down into the earth, reconvey the water back, by circuitous routes, into the depths of the Canyon, there to add to the flow of the Colorado.

Rain at El Tovar. Take rain that falls, for instance, at El Tovar itself, within sight of the Canyon. After a heavy storm, the visitor may see it dashing down the Bright Angel Wash (up which the railway runs) to Ba.s.s Station, where it turns and enters the narrower section of the Wash. It flows in a general southwesterly direction, and enters the Coconino Wash, which discharges into the open plain, once the bed of the great inland Eocene Sea. Here it disappears.

An Underground Stream. In this plain are some breaks in the rocky bed, which allow the water to flow down to join the underground current of the Havasu (or Cataract) Creek, which runs on the northern slope of Bill Williams Mountain. This underground stream (as explained in the chapter on Havasu Canyon) emerges at the head of the village of the Havasupai Indians, in a thousand springs, and then flows on, over several precipices, to the lower levels, thus making the exquisite waterfalls that have rendered this Canyon world-famous. It finally reaches the Colorado some fifteen miles away, where its clear blue waters are soon lost in the muddy flood of the "Red."

Water in the Canyon. After one has ridden in the hot summer sun over this waterless region, and seen the waterwagons of the miners and sheep men, and the great train of water-tanks being hauled for the guests at El Tovar, it is a surprise and a wonder to find below, in the heart of this rocky-walled Canyon, a mighty river dashing its headlong way to the west. Many a time, after a week of riding horseback on the plateau above, until every particle of moisture seemed to have evaporated from my body, have I gone down the trail to the river and camped there, enjoying a swim several times a day, and rowing up and down one of the quiet stretches, between the rapids, where boating is not only possible but reasonably safe. In the Bright Angel and the Shinumo on the north side, and the Havasu on the south side, one may swim, or at least soak and paddle, in cooling waters, where waving willows, giant sycamores, and green cottonwoods sway above the streams, and rich verdure of great variety lines their banks. What a wonderful contrast,--above and below!

Difference between the Rim and the River. Another remarkable difference, or surprise, is found when one leaves the rim above, where the weather is lovely and there is not a sign of rain, and go below to the river, which gives evidence of a great rise. How can the river rise without rain? Yet it seems to, and one almost doubts the evidence of his own senses.

Experience on the River. Engineer Stanton tells of an experience as his party went through the river: "About 2:30 P. M. we heard a deep, loud roar, and saw the breakers ahead in white foam. With a great effort we stopped upon a pile of broken rock that had rolled into the river. When we went ahead to look, much to our surprise, the whole terrible rapid that we had expected to see had disappeared, and there was only a rushing current in its stead. While we stood wondering, there rose right at our feet those same great waves, twelve to fifteen feet in height and from one hundred to one hundred and fifty feet long across the river, rolling down stream like great sea waves, and breaking in white foam with terrible noise. We watched and wondered and at last concluded that this was the forefront of a vast body of water rolling down this narrow trough from some great cloud-burst above. (We learned afterwards that there had been such a cloud-burst on the head-waters of the Little Colorado.) Believing that discretion was the better part of valor, we camped right there on that pile of rocks, fearing that, although our boats would ride the waves in safety, we might be caught in one of these rolls just at the head of a rapid, and, unable to stop, be carried over the rapid with the additional force of the rushing breakers."

High and Low Water. The piles of driftwood found on the rocks in the Canyon reveal a difference of upwards of two hundred feet between high and low water. This, however, does not refer to the general condition of high water, but to exceptional cases. As, for instance, I myself once saw a ma.s.s of rock, the whole face of the cliff, containing doubtless millions of tons, fall into the trough of the stream. The whole course was at once dammed up, and the river rose sixty feet in one hour before the princ.i.p.al ma.s.s of rock was made topheavy by the power of the flood. Then it rolled over with the force of the millions of tons of water behind it, and crumbled as it rolled. The mighty wave dashed on, carrying everything before it. In less than another hour the rock ma.s.s had disappeared, and the water had resumed its normal level. A rise of fifty to seventy feet is not so very unusual in the heart of the gorge, where it is narrow and the waters would necessarily pile up. To see such a rise, without any evidence of a rain above, is a wonderful experience that one occasionally enjoys.

Snow on the Rim. Another remarkable contrast is observed by winter tourists. On the rim at El Tovar, Grand View, or Ba.s.s Camp snow may fall during December, January and February, and sometimes in March, though it quickly disappears. This is not surprising when one considers the high alt.i.tudes. The weather is then sometimes quite frigid, but it is a dry cold which rapidly yields to the warm midday sun. Do not imagine from this general statement that winter, as we know it in the East, is the usual thing at the Canyon. Quite the reverse. There are more sunshiny, warm, windless, stormless and no-snow days than otherwise, taking one year with another. Real winter weather often stays away until well into January. Some years it is a negligible quant.i.ty. At no time need it be feared by the traveller.

Trails in Winter. The trails for half a mile, or even a mile, down into the Canyon, during a part of the winter, are sometimes covered with light snow.