LOWER GEYSER BASIN.—FIREHOLE RIVER.

Between the Upper and Lower Geyser Basin is a space of two or three miles entirely free from hot springs; yet the abundance of spring deposit over all the valley shows that the region was once the scene of great thermal activity; the bottom over which the river flows is paved with silica. Vegetation grows remarkably rank along the stream, and in the valley where the crust of silica does not prevent it, the perpetual warmth caused by the proximity to the springs being very favorable to the growth of plants. The forest grows close down to the margin of the river, making travel very difficult, and in one place the hills of trachyte almost close in the valley.

At the upper end of the basin—which comprises an area of about thirty square miles—are three large boiling springs, on the west margin of the river; nearly opposite are three more, and a short distance below, on the same side, four or five more. Anywhere else these springs would be accounted marvels; but they are so eclipsed by a group a few rods further down the stream that we can give them only a passing glance. This group includes some of the grandest hot-springs in the world. The most formidable is near the margin of the river. Dr. Hayden says:

"It seems to have broken out close by the river, and to have continually enlarged its orifice by the breaking down of its sides. It evidently commenced on the east side, and the continual wear of the under side of the crust on the west side has caused the margin to fall in, until an aperture at least 250 feet in diameter has been formed, with walls or sides twenty to thirty feet high, showing the laminÆ of deposition perfectly. The water is intensely agitated all the time, boiling like a caldron, from which a vast column of steam is ever rising, filling the orifice. As the passing breeze sweeps it away for a moment, one looks down into this terrible seething pit with terror. All around the sides are large masses of the silicious crust that have fallen from the rim. An immense column of water flows out of this caldron into the river. As it pours over the marginal slope, it descends by numerous small channels, with a large number of smaller ones spreading over a broad surface, and the marvellous beauty of the strikingly vivid coloring far surpasses anything of the kind we have seen in this land of wondrous beauty—every possible shade of color, from the vivid scarlet to a bright rose, and every shade of yellow to delicate cream, mingled with vivid green from minute vegetation. Some of the channels were lined with a very fine, delicate yellow, silky material, which vibrates at every movement of the waters. Mr. Thomas Moran, the distinguished artist, obtained studies of these beautiful springs, and from his well-known reputation as a colorist, we look for a painting that will convey some conception to the mind of the exquisite variety of colors around this spring. There was one most beautiful funnel-shaped spring, twenty feet in diameter at the top, but tapering down, lined inside and outside with the most delicate decorations. Indeed, to one looking down into its clear depths, it seemed like a fairy palace. The same jelly-like substance or pulp to which I have before alluded, covers a large area with the various shades of light-red and green. The surface yields to the tread like a cushion. It is about two inches in thickness, and although seldom so tenacious as to hold together, yet it may be taken up in quite large masses, and when it becomes dry it is blown about by the wind like fragments of variegated lichens."

Near this magnificent spring is a hill of silica with a spring 150 feet in diameter on its summit. It is known as the Cauldron. The water boils up in the centre, and overflows with such uniformity on all sides as to form a succession of ornamental steps, from one to three inches in height, just as water would freeze in flowing down a gentle declivity. It has the same transparent clearness, the same brilliancy of coloring, as the spring above described, but the hot steam and the thinness of the rim prevented an approach near enough to observe its depth, or ascertain its temperature, except at one edge, where it was 180°. The average temperature of twenty of the springs of this group was 184°.

About a mile below this group, on the west side of the river, are four small lakes, with quiet surfaces and water as blue as the sky. One of them is nearly half a mile in length. Their water is cold at the present time, but their basins give indications of their having once been enormous hot springs.

A mile or so further down the river is a group of a hundred or more important springs besides a countless number of unimportant and dead springs, covering a space of nearly a square mile. Only a few of them can be specially noticed here. One, on the right bank of the river, is called the Conch Spring, from the resemblance of its basin to a shell, eight feet by ten.

A little below the Conch Spring, on the very margin of the river, is a fine geyser, which has built for itself a crater three feet high, with a shell a foot thick. The inside of the crater is about six feet in diameter. The water is in constant agitation; sometimes it will boil up so violently as to throw the entire mass up four feet, and then it will die down so as to boil like a caldron. The water is perfectly clear, and the overflow forms a stream six inches wide and two inches deep, passing down the sides of the crater and thence into the river along a most exquisitely decorated channel. The entire surface of the crater is covered with pearl-like beads, formed by the spray. A section of the crater shows it to have been built up very slowly, in thin laminÆ. Another spring has a crater like a horn, about a foot in diameter at the top and six feet at the base. It is called the Horn Geyser. It is in constant ebullition, and has the same ornamentations as the one just described. A spring on a level with the river has an enormous square basin, thirty feet across, of unknown depth. It is called the Bath Spring. A little below is another basin of wonderful beauty, called the Cavern. The water issues from several apertures beneath the crust near the margin of the river. The basin itself is fifteen by twenty feet, and twenty feet deep. Nothing can exceed the transparent clearness of the water; the slightest object is reflected in its clear depths, and the bright blue tints are indescribable. Mud springs are also numerous and important in this group. As usual, they are of all sizes, from an inch or two to twenty or thirty feet in diameter, with contents varying from turbid water to stiff mud. They seldom have any visible outlet, but are in constant agitation, with a sound which varies with the consistency of the contents; several give off a suppressed thud as the gases burst their way through the stiff mortar. Sometimes the mortar is as white as snow; sometimes brown, or tinged with a variety of vivid colors. One mud spring, located in the woods near a small lake, northeast of the Cavern, has a basin thirty by forty feet, with sides fifteen feet high. It is in constant action, frequently hurling the mud outside of the rim. All around it are a number of little vents, which keep up a simmering noise. Some of these vents have built up little cones, from four to twelve inches high, many of them sealed at the top. On removing the cone, the inside is found to be lined with delicate crystals of sulphur, deposited from the steam.

On the opposite side of the river, along a little branch that flows in from the west, is a considerable group of geysers and boiling springs. Near the base of the mountains is a first-class boiling spring with a curious fungus-like rim. It is always in violent agitation, sending forth great columns of steam. It flows from beneath a hill, and is surrounded with springs whose silicious deposits take the form of the toad-stool fungus. Some of this group may be called spasmodic springs. One, with a most beautifully scalloped rim, fifteen by twenty feet in diameter, is always boiling, and occasionally explodes with great violence, shooting its water several feet into the air.

Along the eastern side of this Lower Geyser Basin are several extensive areas abounding in mud-springs, boiling springs and geysers, whose infinitely varied characteristics can have no more than the briefest notice. Beginning at the north, the first that commands attention is that whose central object of interest is the Thud Geyser, so called from the peculiar noise it makes as the water rises and recedes. It is situated on the slope of a small hill, is about twenty feet in diameter, and has a crater five feet wide and five high, composed of geyserite of a greyish color, full of deep pockets containing balls of the same material, about the size of walnuts, each one covered with little rosette-like formations. The column of water thrown out by this geyser during its eruptions is very wide, and reaches the height of fifty feet. Near it was obtained some pieces of wood, coated with geyserite of a delicate pink tinge: the silica had thoroughly penetrated the woody fibre. There were found, also, pine-cones coated in the same manner, forming beautiful specimens. A few yards back of the geyser are three large mud-springs, in one of which the mud is red, in another white, and in the third pink—the jets of steam causing the mud to assume the form of small conical points throughout the basins. They are situated in a bed of clay, the red color being due to iron. Below these latter are some chalybeate springs whose bright-red iron deposit have spread over a considerable area, in glaring contrast with the white color of the silicious deposits of their neighbors.

In the same group is a fissure spring forty feet long, four feet wide and ten deep, clear as crystal; also a large basin nearly circular, fifty feet in diameter with a number of huge apertures, some of which throw up water thirty feet. One orifice shoots a constant stream six feet high. All around this geyser-group are smaller springs continually bubbling, and large numbers of small geysers, some constantly playing to heights not exceeding ten feet, while others merely keep up a violent ebullition, rising and falling with a pulsating motion. There is also one beautiful quiet spring, with a basin so large that it looks like a small lake. Into its clear depths one may look down thirty or forty feet, beholding a fairy-like palace adorned with more brilliant colors than any structure made by human hands. The aggregate waters of the group form a little stream which flows westward into the small lake already noticed in connection with the mud-springs at the lower end of the basin.

South of the Thud Geyser is a large basin 150 feet in diameter, enclosing a crater twenty-five feet in diameter. From the inner crater the water is thrown up in a vast column sixty feet high, falling back in silver-white globules, a natural fountain of marvellous beauty. A short distance south of this Fountain Geyser is the most remarkable mud-pot in the Firehole valley. Its surface, forty by sixty feet in diameter, is covered with large puffs, which, in exploding with suppressed thuds, throw the hot mud several feet into the air and spatter the broad rounded rim in every direction. The mud is an impalpable silicious clay, of every shade of color from the purest white to a bright pink. Within a few feet of this mud-spring is a large clear spring sixty feet across, with perhaps fifty centres of ebullition. It is filled with the rusty, leathery deposit already described, and all around the basin where the waters overflow is an extensive deposit of iron.

A quarter of a mile east of the mud-springs, at the northwestern base of a mountain-spur and extending a thousand yards up a ravine, is a group of springs occupying a space five hundred yards wide. One of these, the Fissure Spring, is a hundred feet long and from four to ten feet wide. Quite a large stream flows from this spring. Many of the surrounding springs remain full to the rim, and are in constant ebullition, yet no water flows from them. Others discharge great quantities of water. In this group are three sulphur springs, the only ones in the region: the sulphur present however is not very abundant. Silica and iron seem to be the dominant constituents of nearly all the deposits. Some of the springs send forth a disagreeable odor, and deposit a curious black sediment like fine gunpowder. Near the centre of the group is a small lake 600 feet long and 150 wide. By its eastern shore is a geyser which spouts very regularly to the height of fifteen or twenty feet. West of the lake are two small geysers cones incrusted with a cauliflower-like formation; near them in a fissure are balls of geyserite coated in the same manner.

A thousand yards further south, in the southeastern corner of the basin, is a ravine a mile and a half long and three hundred yards wide, occupied by a most interesting group of springs and geysers. Just below the mouth of the ravine, on a mound fifteen feet high, is a large cone twenty-five feet high, probably a geyser. Steam issues steadily from the top with the sound of a high-pressure engine. It is called the White Dome Geyser.

In this lower basin there are very few raised craters, the most of the springs and geysers having funnel-shaped basins, with rims of various forms, but mostly circular. In this group there is besides the White Dome a small cone with its top broken off. It is four feet in diameter, with an aperture eighteen inches across. It is called the Bee-hive, For several feet around on all sides the surface of the ground is ornamented with pearly tubercles of silica, from the size of a pea to three inches in diameter. The spring basins in this group have every variety of form. One, a fine boiling spring, has an oval rim five feet by eight, its sides running straight down beyond the reach of vision. Another is funnel-shaped, tapering to a narrow aperture, with a scalloped rim, projecting several inches over the water. Some springs discharge no water; others send forth a stream two feet wide and six inches deep. In one of the streams, the channel of which is about two feet wide and one foot deep, the water is filled with a plant with a pinkish-yellow base, bordered with a very fine green silky fringe, perpetually vibrating with the flowing waters. "Except that they were a rich vegetable green, these fringes had the form and texture of the finest cashmere wool. The luxuriant growth of vegetation in and along the borders of these little streams," adds Dr. Hayden, "was a wonder of beauty. The whole view was there superior to anything of the kind I had seen."

In some of the springs Dr. Hayden's assistants found butterflies which had fallen in and been scalded to death. On taking them out they were found to be partially petrified, and coated with silica.

At the mouth of the ravine is the principal geyser of the group. Its basin is circular and about 60 feet in diameter, although the spring itself, which is in the centre, is only about 15 or 20 feet in diameter. The incrusted margin is full of sinuses, filled with hot water, which falls into them whenever the geyser is in operation. These pockets contain also smooth pebbles of geyserite, varying in size from that of a pea to a large-sized walnut, rounded by the action of the water. The water in the spring of the geyser is of a blue color and in constant agitation, though more violently so just before spouting. The column of water projected reaches the height of 100 feet, and is accompanied by immense clouds of steam.

Not far from this geyser is an elegantly scalloped spring, nearly circular, twenty-five feet in diameter, and with vertical sides to an unknown depth. The entire mass of the water is most violently agitated at times, and, overflowing the sides of the basin, passes off in terrace pools or reservoirs to the main stream, producing a system of architecture out of silica similar to that of the calcareous springs on Gardiner's River. The gay colors, from bright pink to delicate rose, are well shown.

The valley is filled with springs up to its very source; and springs which burst from the mountain side, eight hundred feet above the level of the basin, have temperatures ranging from 166° to 180°. Tracing one exceptionally cool stream up the south side of the caÑon, Dr. Hayden found on the almost vertical side of the mountain a little spring so imbedded in bright green moss that it could hardly be seen.

"With great difficulty," he says, "we managed to climb up the mountain side, and, clearing away the moss, obtained the first water that we could drink for eight hours. In all of our examination during the day we had not found a drop of water of sufficiently low temperature to take into our mouths, though there were hundreds of the most beautiful springs all around us. We were like Coleridge's mariner in the great ocean, 'Water, water everywhere, but not a drop to drink.'"

Looking back over the valley the morning before his departure for the Upper Basin, Dr. Hayden saw it literally filled with columns of steam, ascending from more than a thousand vents. "I can compare the view," he writes, "to nothing but that of some manufacturing city like Pittsburgh, as seen from a high point, except that instead of the black coal smoke, there are here the white delicate clouds of steam. Small groups or solitary springs that are scattered everywhere in the woods, upon the mountain-sides, and which would otherwise escape observation, are detected by the columns of steam. It is evident that some of these groups of springs have changed their base of operations within a comparatively recent period; for about midway on the east side of the lower basin there is a large area covered with a thick, apparently modern, deposit of the silica, as white as snow, while standing quite thickly all around are dead pines, which appear to have been destroyed by the excessive overflow of water and the increased deposition. These dry trees have a most desolate look; many of them have fallen down and are incrusted with the silica, while portions that have fallen into the boiling springs have been reduced to pulp. This seems to be one of the conditions of silicification, for when these pulpy masses of wood are permitted to dry by the cessation of the springs, the most perfect specimens of petrified wood are the result. In one instance a green pine-tree had fallen so as to immerse its thick top in a large hot basin, and leaves, twigs, and cones had become completely incrusted with the white silica, and a portion had entered into the cellular structure, so that when removed from the water, and dried in the sun, very fair specimens were obtained. Members of my party obtained specimens of pine cones that were sufficiently silicified to be packed away among the collections."

Grasshoppers, and even butterflies, as we have seen, are occasionally subjected to the same treatment, with the same result. By-and-by, when the geyser regions become a popular resort, the preparation of petrifactions to be carried away as mementos, may become quite an item of entertainment if not of industry.

To obtain a complete view of the Lower Geyser Basin, Colonel Barlow made a trip to the summit of the Twin Buttes on the west side of the basin. From this point the valley of Firehole River could be overlooked for a distance of twenty miles; but nothing new was discovered except an attractive fall plunging over a precipice a short distance to the south.

After much severe climbing over rocky ridges, and scrambling through deep and thickly wooded ravines, he succeeded in reaching the foot of the fall—the loveliest vision he had ever beheld. "Towering above my head," he writes, "was a perpendicular cliff, three hundred feet high, while from a slight depression in its upper edge descended a sparkling stream, dashed into spray as it impinged against projecting angles of the rocky wall. On reaching the bottom the mist is gathered into a shallow basin, forming a pool of clear cold water, delightfully refreshing in this region of steaming geysers and volcanic heat. After resting a moment in this quiet retreat, the water slowly finds its way through the forest, and crossing the geyser valley eventually reaches Firehole River, some two miles distant."

From the marshy ground about the fall the pines shoot upward to an astonishing altitude, as though ambitious to overtop the cliff. Colonel Barlow approached the fall through a natural avenue in these pines, and as he caught sight of its dancing water, leaping with life-like action down the face of the overhanging cliff, the thought of fairies was so strongly suggested that he could think of no name so appropriate as the Fall of the Fairies.

The extreme north of the Lower Basin is bounded by the East Fork of Madison River, along whose valley, within the basin and above it, are numerous groups of interesting springs, though not materially different from those already described. Near the head of the stream sulphur springs are abundant, with here and there extensive deposits of sulphur. Steam-vents are frequent, their orifices lined with sulphur, and the surrounding crust filled with crystals of a vivid yellow. The channels of the streams are lined with a delicate veil of creamy sulphur. In some of the springs, lower down the stream, iron predominates. Within the basin on the south side of the East Fork are a hundred springs or more, any one of which, if alone, would be worthy of elaborate description. In some the fallen leaves of trees are frosted with silica as white as snow, and the inner surface of the basins are covered with a delicate bead-like embroidery of marvellous beauty. The most beautiful of the group is a Prismatic Spring, like those described in the Upper Basin. "Nothing ever conceived by human art," says Dr. Hayden, "could equal the peculiar vividness and delicacy of coloring of these remarkable prismatic springs." About a mile south of the East Fork, at the head of a little stream that flows into the Firehole, is another of these brilliant springs. A thin, delicately ornamental rim of silica surrounds a basin six feet in diameter, filled to the brim with water of marvellous transparency. When its surface is rippled by a passing breeze, the reflected sunlight is broken as by a million prisms. It is called the Rainbow Spring.