Gold strikes on the Clearwater, Salmon, Owyhee, and Boise tributaries of Snake River in the opening years of the 1860’s led to establishment of the “Idaho mines,” from which prospectors moved eastward, across the Continental Divide, to yet another goldfield. But the placers on Grasshopper Creek, where the town of Bannack sprang up in 1862-63, were disappointing to many and they continued to search for gold east of the Rocky Mountains.
Among the latter were 40 prospectors who banded together under “Colonel” Walter Washington deLacy to explore the headwaters of Snake River in the late summer of 1863. By the time they reached the forks of Snake River and were within the south boundary of the present park, the party had splintered several times, and another division near that place resulted in Charles Ream leading a group up Lewis River to Shoshone Lake, over the divide to the Firehole River and down that stream to the Madison, while deLacy conducted his party across the Pitchstone Plateau to Shoshone Lake, then over the divide by way of DeLacy and White Creeks into the Lower Geyser Basin, from which they, too, continued down Firehole River to the Madison and out of the Yellowstone region proper.
Two years later deLacy, who was a well-trained civil engineer, prepared a map of the Territory of Montana which was used by the First Legislative Assembly for laying out the original counties,  and the discoveries made by the 1863 parties were thus made public knowledge. The principal contribution of deLacy’s map to the geographical knowledge of the Yellowstone region was its essentially correct delineation of the Lewis River headwaters of the Snake. He was the first to show that branch as heading in what is now Shoshone Lake (he did not name the Lake,  though he noted its hot spring basin; see map 7). Thus, he avoided the mistake made by DeSmet in 1851, and later by the Hayden Survey, in assigning Lewis and Shoshone Lakes to the Madison drainage. This map also indicated the geyser basins of the Firehole River in its label, “Hot Spring Valley.”
It is sometimes claimed that deLacy forfeited his right to consideration as the discoverer of Yellowstone’s thermal features because he did not adequately publish his findings, a line of reasoning which assumes he was too much concerned with prospecting to appreciate the wonderful region he passed through. However, an excerpt from one of his letters which found its way into print in 1869 shows that he understood both the extent and the nature of the thermal areas he saw, for he wrote: “At the head of the South Snake, and also on the south fork of the Madison, there are hundreds of hot springs, many of which are ‘Geysers’.” 
The extent of deLacy’s familiarity with the southwestern quarter of what is now Yellowstone National Park is evident in the account he later published from notes made in 1863 (cited in Note 85):
[p. 128] We had not traveled more than three miles next day (September 5th), when we came to the forks of the stream that we had been ascending. One branch came from the northeast [Snake River] and the other from the north [Lewis River], and there were hot springs with cones four or five feet high near the junction. Neither of the streams were large, and it was thought that we would soon reach the divide. It being impracticable to go up either branch, on account of fallen timber, we commenced climbing up the mountain side to the west, where the timber was more open, and after ascending about one thousand feet with much difficulty, reached a large open prairie, apparently on the summit, [p. 129] where there were two small lakes, of a beautiful blue, and small streams flowing in opposite directions.  I judged that one of them ran into the North Snake [Henrys Fork]. Here we stopped for dinner.
Here another split of the party took place. Some of the men had noticed veins of quartz, as they supposed, down below, and resolved to return and examine them. This left me about thirteen men to go forward with.
Our friend Brown had been completely disgusted, during the last few days, with his whip-saw, owing to the number of times every day that he had to stop to adjust the pack in going through the woods, and now left that useful implement leaning against a tree, with the remark that “he had packed the damned thing far enough.”
On starting, we kept a northerly course and passed over low undulating ridges, covered with open pine timber [Pitchstone Plateau]. The rocks, where exposed, seem to be vitrified sandstone. We killed two deer this evening which was the first large game shot on the trip. After traveling several miles, we saw an opening beneath us which looked like a valley, and descending the mountain, which was very steep and high, reached a small stream flowing northeasterly [Moose Creek], just about dark, and camped where there was plenty of grass, wood, and water.
In the morning (6th), we descended the stream for about five miles, and to the great surprise of us all, came to the bank of a large lake [Shoshone]. We were all lost in conjectures as to what it could be. Some thought that it must be the Yellowstone Lake, and others that it must flow into the Madison or Gallatin. We finally resolved to go around the southern end,  which was not very far from us apparently, and then go around the other side. We then traveled along the lake shore for some three or four miles, when we came to [p. 130] the outlet of the lake, a large stream flowing south into Snake river. Instead of going around the head, as we had thought to do, we had been going around the foot.
One thing puzzled me. The outflowing stream was much larger than either of the forks of the South Snake that we had left before. I afterward found out, however, that it flowed into another lake, now called Lewis Lake, from one of the men who went back at our noon halt.
This party which left us, had returned to the forks, and not finding the quartz, as they expected, ascended the stream coming from the north. They encountered a fire in the woods which gave them some trouble, and found some very high falls in the stream. They passed Lake Lewis, and came to the foot of the large lake, where they found our old camp. Here they went up the west side of the lake to its head, and there found a large number of hot springs [Shoshone Geyser Basin], some of which were geysers, which they saw in action, spouting up the water to a great height, and thence went over to the South Fork of the Fire Hole river, where they again saw our camps, and thence down the Madison river to Virginia City. These facts I obtained afterward at Bannack City, from Mr. Charles Ream, one of the party, and it was thus established conclusively that the large lake was the head of the South Snake, and I was enabled to correct the course of the Madison river, and connect my surveys with it. . . .
To return to our own party. We camped at the mouth of the lake and prospected and hunted for the rest of the [p. 131] day, but without any success. The lake seemed to be about ten or twelve miles long, running northwest and southeast, and to be surrounded by low and thickly wooded hills which came down to the water’s edge. There was a point projecting into the lake on the west side, which hid a large part of the lake from us, although we did not know it them.
On the next day (7th), we went up the eastern side, near the water, passing through scrubby pines, without underbrush. There were many game trails made by the wood buffalo, whose tracks appeared numerous and fresh. We did not see any, and finally, at noon, stopped on a small prairie, for dinner. In the evening we left the lake altogether, and took a northerly course, hoping to cross the divide to some other stream. Our course lay through timber, and over and around fallen logs, but the ground, though undulating, was not rocky, and we found many game trails leading in our direction.
Whenever we could obtain a glimpse of the outside world, we could see high ranges of mountains on every side. We kept on till late, without finding any place to camp, but just at dark arrived at a small dry prairie, where we camped [DeLacy Park].  There was a damp place in the center, where, by digging about three feet, we soon obtained water for both ourselves and animals . . . [p. 132] It rained heavily during the night and also during the next day, and we remained here, as we now had plenty of water and grass.
On the 9th, we continued our journey, and after traveling three miles, descended the mountain side into an open country. In another mile we reached the head of a small stream [White Creek], the water of which was hot, and soon entered a valley or basin, through which the stream meandered, and which was occupied on every side by hot springs. They were so thick and close that we had to dismount and lead our horses, winding in and out between them as we best could. The ground sounded hollow beneath our feet, and we were in great fear of breaking through, and proceeded with great caution. The water of these springs was intensely hot, of a beautiful utramarine blue, some boiling up in the middle, and many of them of very large size, being at least twenty feet in diameter and as deep. There were hundreds of these springs, and in the distance we could see-and hear others, which would eject a column of steam with a loud noise. These were probably geysers, and the boys called them “steamboat springs.” No one in the company had ever seen or heard of anything like this region, and we were all delighted with what we saw. This was what was afterward called the “Lower Geyser Basin” of the Madison, by Prof. Hayden.
We thus went on for several miles, stopping occasionally [p. 133] to admire the beauty, variety, and grandeur of the sight, and at length came to a large stream flowing northerly [Firehole River], near the banks of which were scattering hot springs, and some of which had been hot once, but had now cooled apparently, the water being tepid and muddy, with a strong smell of sulphur.
We “nooned” on the left bank of this stream, and then continued our way north, crossing the river again, by a deep ford, in about three miles, and camped for the evening on the edge of a small prairie, near where a large fork came in the southeast [Gibbon River]. On the left bank of the south fork was a high, perpendicular wall of rock,  and we could see the smoke of hot springs up the east fork [Terrace Spring].
We had great discussions in the evening as to where we were, some thinking we were on the North Snake river, and others that we were on the Madison. The map which I had, represented the North Snake river as running around and leading to the northeast of the South Snake, and these streams seemed to run that way. In reality, we were at the forks of the Fire Hole river, a branch of the Madison.
In the morning (September 10th), we continued our journey down the main river, crossing the east fork just above the junction. The weather looked stormy and threatening. The main river was about fifty yards wide, its valley very narrow, with high, rocky hills on either side covered with pine, and the general course westerly. After traveling about five miles, rain came down heavily, and we were forced to go into camp on the river, and at the head of what appeared to be a cañon.
In the evening, during an interval of calm, I went forward on the trail across the mountain to explore. In about one and half miles I came to the foot of the cañon, [p. 134] when I perceived that the country opened out into a large basin [Madison Valley], through which the main river ran.
Unlike the Ream party, which passed down the Madison River after leaving the Yellowstone region, deLacy turned north, crossing the Madison Basin to the pass leading to the West Gallatin River, which he followed down to Spanish Creek.<
One of the men who accompanied deLacy in 1863 returned to the Yellowstone region the following year. He was John C. Davis, a member of James Stuart’s 1864 expedition down the Yellowstone River to prospect the Bighorn and Stinkingwater (Shoshone) Rivers. Upon the breakup of that venture, a remnant of the party worked southward under the leadership of Adam “Horn” Miller. Six of these men eventually reached Jackson’s Hole, from which Davis and two others left for the Yellowstone region. He says,  according to the Louisville, Ky., Courier-Journal:
We came into the park just above the lake, and immediately found ourselves in the midst of the wonders of this enchanted land. The boiling springs and geysers were all around us, and, accustomed as we were to the marvels of Western scenery, we hardly knew what to think of the phenomena. Having visited this place the preceding year I was, however, less surprized than the others. We wandered along the shore for a while, and leaving the lake we went into camp about a mile and a half above the falls. The roaring of the great cataract reached us, but was barely discernible at this distance, and we were among so many wonders that we paid it little attention. After camping I took my gun and started out in the hope of finding an elk for dinner. I went down the bank, and in short time came to the Upper Falls. The full grandeur of the scene did not burst on me at once. Men who have engaged in a hand-to-hand struggle for a frontier existence lose sentiment after a few years; but when I realized the stupendous leap of water, I could not help being impressed. I stood gazing at it for a long time, and I remember estimating the height of the falls at only about 200 feet. 
I did not then think that I was the first white man to behold one of the greatest wonders of the Western world.
In the afternoon we crossed the river on our ponies. Going below we reached the Grand Canyon, along which we wandered for a short distance. I remember that we crept to the edge and looked over to where the river, a mere silvery thread, was winding its way in silence and darkness 1,200 feet below where we stood. After we crossed we remain in the valley awhile, and then there was again a division of the party.  William Armstead and Johnston Shelton, both Scotchmen, returned with me to Virginia City, or Alder Gulch, as it was then called.
We saw plenty of Indian signs, but we fortunately eluded any of these gentry. Shortly afterwards one section of our party were attacked by a hostile gang of Crows, and a man named Harris was killed. The interpreter of the original party was with this company, and he was also captured, but he afterwards made his escape by ingratiating himself with the chief.
When we first reached the volcanic region of the geysers we were much alarmed at the yielding of the ground. Finally we struck a buffalo track, and followed this with some feeling of safety. None of our party thought to give names to anything in the valley. I remember one little incident connected with Pelican Creek, however, which may have suggested its name. We camped on this creek, and noticed several large birds which appeared to be wild geese. I shot one, which managed to fly out some distance in the lake before it fell. I swam out after it, and became very much exhausted before I reached it. It looked as if it might be good to eat so I skinned it, and then the boys concluded it would hardly do. I hung the pelican—for that was what it was—on a tree, and it was found afterward by Miller, who came by with his party. 
The editor of the Courier-Journal appended this comment to the Davis account: “It would be remembered that the first public announcement of the valley’s discovery was made after the visit of an exploring party in 1869 (Folsom party). Before this it had been visited by hunters, but there is no account of any visit prior to that of Mr. Davis, and it seems that he and his party are entitled to the honor of its discovery, though they failed to make use of the lucky accident. His story can be vouched for.”
Other prospectors were in the Yellowstone region that summer. Thomas Curry’s discovery of gold at “Curry’s Gulch” (later known as Emigrant Gulch) in the late fall of 1863 brought a well-equipped party under George A. Huston the following spring. But most of the reinforcement thought they could do better and continued up the Yellowstone River and its “East Fork” (now Lamar River). The scanty information available on their adventure comes from two writers who knew many of the participants personally. E. S. Topping says:
. . . Prospecting parties were going out in every direction. One of these consisting of thirty men under the leadership of Austin [George A. Hustin], went to and up the Yellowstone. When they arrived at the east fork of the Yellowstone, they went up that stream to the first creek coming in from the left above Soda Butte creek, up which they went. They made a camp at its head and, as they had seen no signs of Indians, let their horses run loose. The next morning at daylight a band of Arrapahoes swooped in and drove away all their stock but one jackass. It was useless to chase them without horses, and the boys, not being ready to go back, cached their things and, packing the jackass heavily and themselves lightly, went over the divide to Clarke’s Fork and down it to below the mouth of the canyon. Here they found some prospects, but no pay; so turned back to their cache, and taking from this the most valuable articles, struck out on their back trail for Virginia City. 
Superintendent Norris elaborates somewhat on that in his annual report for 1881:
In the spring of 1864, H. W. Wayant, now a leading citizen of Silver city, Idaho, William Hamilton, and other prospectors, to the number of forty men, with saddle horses, pack train, and outfit, ascended the east side of the Yellowstone from the Gate of the Mountains to Emigrant, Bear and Crevice Gulches, forks of the Yellowstone, East Fork, and Soda Butte; thence over the western foothills of Mount Norris to the bluffs upon the south side of Cache Creek, where their horses were all stolen by some unknown Indians, but their only two donkeys would not stampede, and remained with them. Here the party broke up; Wyant, Harrison, and ten others, with one jack, and what he could carry, ascended Cache Creek to Crandall Creek, Clarke’s Fork, Heart Mountain, thence by way of Index Peak and the Soda Butte returned to the cache made by the other party of what they could not carry, aided by their donkey, from where set afoot, and hence called Cache Creek.
Norris adds that “Later in the same season George Huston and party ascended the main Fire Hole River, and from the marvelous eruption of the Giantess and other geysers, and the suffocating fumes of brimstone, fearing they were nearing the infernal regions, hastily decamped.” 
The Yellowstone region was visited a number of times in 1865. A Montana prospector and mountaineer named George Harvey Bacon is said to have reached the Upper Geyser Basin with a party of Indians,  and Jim Bridger passed entirely through the area with three ex-trappers—John Dunn and two others.  Another former trapper, James Gemmel, is said to have passed through the Yellowstone region with his daughter, Jeanette (who may have been the first white woman to enter the area),  but the most interesting visitor that year was Father Francis Xavier Kuppens, a Belgian priest of the Jesuit Order, who had this recollection to offer 32 years later:
[p. 400] About the years 1865-66 I was stationed at the old Mission of St. Peter’s on the Missouri River near the mouth of Sun River. A great part of that winter [1864-65, according to other records] and spring I spent with the Pigeon [Piegan] Indians roaming from place to place south of Fort Benton, and on the Judith River. It was while leading this nomad life that I first heard of the Yellowstone. Many an evening in the tent of Baptiste Champagne or Chief Big Lake the conversation, what little there was of it, turned on the beauties of that wonderful spot. I do not know that the narrator always adhered strictly to facts, but making allowance for fervid imagination there was sufficient in the tale to excite my curiosity and awaken in me a strong desire to see for myself this enchanted if not enchanting land. In the spring with a small party of Indians hunting buffalo, I persuaded a few young men to show me [p. 401] the wonderland of which they had talked so much. Thus I got my first sight of the Yellowstone. I shall not attempt to describe it, that has been done by many abler pens than mine; but you may be sure that before leaving I saw the chief attraction,—the Grand Canon, hot and cold geysers, variegated layers of rock, the Fire Hole, etc. I was very much impressed with the wild grandeur of the scenery, and on my return gave an account of it to Fathers Ravalli and Imoda, then stationed at the old Mission of St. Peter’s. 
The effect of Father Kuppens’ visit on the definitive exploration of the Yellowstone region will be considered in Part II.
The hostility of the Sioux Indians, who were determined to prevent a reopening of Bozeman’s emigrant road into Montana Territory, hampered the activity of prospectors in the Yellowstone region during 1866. Only one incursion into the area has been recorded, and that small party, led by George Huston, entered from the west, up the Madison River, passing from the geyser basins to the Mud Volcano by way of the “east fork” (Nez Perce Creek), around the west side of Yellowstone Lake to Heart Lake, then across rough country to the Yellowstone River above its lake. From there they followed the eastern shore to the outlet, descended the river to the great falls and across the Mirror Plateau to the east fork of the Yellowstone (Lamar River), after which they passed down that stream and the Yellowstone to Emigrant Gulch. 
How much factual information Huston’s far-ranging party brought back is unknown, for contemporary reportage is lacking; but enough was known of the Yellowstone region and its superlative nature to allow the editor of Montana’s first newspaper to compare it with the Yosemite Valley, in these words:
The scenery of the Yosemite Valley, as described by Bowles in his new book, “Across the Continent,” though very grand and peculiar, is not more remarkable than the scenery at the passage of the Yellowstone through the Snowy Range, one hundred miles northeast of this city. The rocks on either side, for a great distance, are equal in height to those of the Yosemite, and the river steals through them with the swiftness and stillness of an imense serpent, leaping into joyous rapids at the point of its release. We should like to have Brierstadt [sic] visit this portion of our Territory. He could make a picture from this piece of scenery surpassing either of his other views of the Rocky Mountains. 
The death of John Bozeman at the hands of Indians early in 1867 led Acting Governor Thomas Francis Meagher to raise and arm “territorial volunteers” who built and occupied two posts intended to serve as barriers against incursions of hostile Indians into the settlements of southwestern Montana. These outposts—Fort Elizabeth Meagher, east of the town of Bozeman, and Camp Ida Thoroughman, at the mouth of Shield’s River—effectively screened the northern approach to the Yellowstone region, allowing a resumption of prospecting in that wilderness.
Interest had been sparked anew by the luck of “Uncle” Joe Brown and three others, who worked a river bar at the mouth of Bear Creek during the fall and winter of 1866-67, taking out $8,000 in gold dust and nuggets. “A. Patron,” writing from that place as spring came, publicized their good fortune in a Helena newspaper through his mention that “the bright scales of 22 ounce gold peculiar to this locality have been washing down the Yellowstone in liberal, unmeasured quantities of late, showing that there must be a heavy deposit above.” 
Among those attracted to the Bear Creek strike was Lou Anderson, who soon moved on up the Yellowstone with a small party. This search for the lode is of interest because of its legacy of three place-names. According to E. S. Topping, the circumstances which generated the names were these:
Early in the summer of 1867, Lou Anderson . . . with [A. H.] Hubble [George W.] Reese, Caldwell and another man, went up the river on the east side. They found gold in a crevice at the mouth of the first stream above Bear, and named it in consequence, Crevice gulch. Hubble went ahead the next day for a hunt and upon his return he was asked what kind of a stream the next creek was. “It’s a hell roarer, was his reply, and Hell Roaring is its name to this day.
The second day after this he [Hubble] was again ahead, and the same question being asked him, he said. “Twas but a slough.” When the party came to it they found a rushing torrent, and in crossing, a pack horse and his load were swept away, but the name of Slough Creek remains. 
Early that summer a notice appeared in the Virginia City newspaper, announcing:
Organized. The expedition to the Yellowstone country mentioned a short time since, is now organized, and it is the purpose of the party to start from the camp on Shield’s river in about two weeks. The expedition will be gone some three weeks and will go up the river as far as Yellowstone Lake. As a number of gentlemen have expressed a desire to join the party, we refer those in Helena to Gen. Thoroughman who will be at that city on Monday, and will give all desired information. Parties here, who have the leisure to make this fascinating jaunt can ascertain particulars from Judge Hosmer or T. C. Everts. 
But that proposal, which appears to have originated in Acting Governor Meagher’s interest in the Yellowstone region (of which more will be said in Part II), was vitiated by his death in the Missouri River at Fort Benton on the eve of departure.
However, the mounting interest in the diggings developing along the Yellowstone River was not lost on the unpaid citizen-soldiers lounging around Camp Thoroughman (renamed Camp Green Clay Smith after Meagher’s death),  and, though their morale was low with regard to all things military, they were willing enough to accompany Capt. Charley Curtis on a scout up the river. 
This expedition was reported in the Virginia City newspaper from information supplied by Dr. James Dunlevy, surgeon for the volunteers, and, though egocentric and couched in hyperbole (possibly an editorial fault), it is yet a very interesting impression, of value for its glimpse of the Mammoth Hot Springs. Here is Dunlevy’s account as rendered by an unidentified “B.G.” 
Dr. Dunlevy left Camp Green Clay Smith, near the mouth of the Yellowstone Canyon, about the 12th ult., with a small party, following up the western side of the river for about ninety or one hundred miles,  and within a few miles of the lake near the head of this great river; traveling through a valley of great extent, richness and beauty, interspersed with scenery of most impressive grandeur and magnitude, unsurpassed in the world. Tall spires of colossal grandeur which in beauty and symmetry are superior to any works of art; beetling cliffs of rock, rising from the waters edge thousands of feet in height; while wood-crowned mountains, with delightful slopes and vista like parks coursed with purling streams and mountains covered with snows, capped and rising to cone shaped peaks and knife-like edges, or turretted like castles, and rolling away off in beautiful white pyramidal forms, were to be seen on every side. Language is not adequate to convey an idea of the marvelous beauty of the scenery, which is beyond the power of description, and begets a wonderful fascination in the mind of the beholder who reverently gazes at the snow-crowned summits, that seem as if “They were to show How earth may pierce to Heaven and leave vain man below.” In addition to this, Dr. Dunlevy informs us that he discovered several large streams coming in from the western side, that are yet unnamed. When near the end of his journey his attention was called to something resembling steam or smoke, near the crest of a mountain, and observing springs of hot water gushing out of its side, he was induced to attempt to reach it, which he succeeded in accomplishing with very little trouble, there to find something that proved to be the key-stone to the arch of wonders—a boiling hot lake, covering an area of about forty acres!  A herd of antelope were quietly licking the salt along the edge, when a shot from his rifle brought one of them down, a sheath-knife soon severed off a ham which was fastened to a lariat and thrown into the lake, and in less than forty minutes it was taken out completely boiled and salted!  The party ate of it and represented it as having a peculiar but pleasant flavor. The Doctor supposed the water to contain a large percentage of tincal, the crude property from which borax is manufactured, and has already taken the necessary steps to have it preempted and a company organized to have it thoroughly tested. . . . We have not the space to give an elaborate report of Dr. Dunlevy’s trip, but can only say that it abounded in the rarest scenes and incidents, equalling almost the experience of Captains Speke and Grant, in their effort to discover the source of the Nile; and we trust ere long that some select party, well prepared and equipped, will be able to penetrate these wilds and reveal to the world its manifest beauties, existing as they do in all their pristine grandeur. The Doctor deserves credit for the daring, invincible spirit displayed by him in thus far exploring this remote region, which example we trust will be emulated by many others. He was compelled to return to camp as his time was limited, and what matches he had with him became dampened and spoiled. He reports the country filled with game of all kinds, including mountain bison, and reports mining in three different gulches on the eastern side of the river, including Bear and Emigrant gulches.”
Prospectors returning to Yellowstone City (at the mouth of Emigrant Gulch) late in August had some information on the country between Mammoth Hot Springs and Lake Yellowstone, and some of it was forwarded to a Virginia City newspaper by David Weaver, a miner who was laboring in the shafts and drains then being constructed to get at the gold below Emigrant Gulch. He says: 
A portion of the Bear Gulch stampeders have returned. They have been to the Lake at the head of Yellowstone and report the greatest wonder of the age. For eight days they traveled thro’ a volcanic country emitting blue flames, living streams of molten brimstone, and almost every variety of minerals known to chemists. The appearance of the country was smooth and rolling, with long level plains intervening. On the summits of these rolling mounds [Crater Hills] were craters from four to eight feet in diameter; and everywhere upon the level plains, dotting it like prairie dog holes, were smaller ones, from four to six inches and upwards. The steam and blaze was constantly discharging from these subterranean channels in regular evolutions or exhaustions, like the boilers of our steamboats, and gave the same roaring, whistling sound. As far as the eye could trace, this motion was observed. They were fearful to ascend to the craters lest the thin crust should give way and swallow them. Mr. Hubbel, (one of the party,) who has visited this region before, ventured to approach one of the smaller ones. As he neared its mouth his feet broke through and the blue flame and smoke gushed forth, enveloping him. Dropping upon his body, he crawled to within a couple of feet of the crater and saw that the crust around its edge was like a thin wafer. Lighting a match he extended it to the mouth and instantly it was on fire.  The hollow ground resounded beneath their feet as they travelled on, and every moment it seemed liable to break through and bury them in its fiery vaults. The atmosphere was intensely suffocating, and they report that life could not long be sustained there. Not a living thing, bird or beast, was seen in the vicinity. The prospectors have given it the significant name—”Hell!” They declare they have been to that “bad place,” and even seen the “Devil’s horns”; but through the interposition of Providence (not to speak profanely) their “souls have been delivered”, and they emphatically aver, if a “straight and narrow” course during their sojourn on the Yellowstone will save them, they will never go there again. On their return, between the Lake and the falls, they encountered four men on four splendid American horses, driving thirty-six large mules, in fine condition, all branded “U.S.” Said individuals wore linen dusters and heavy gold rings on their fingers—travelled southward—understood the country—acted suspiciously, and that’s all that’s known. 
Another party of prospectors passed through the Yellowstone region in the fall of 1867, and, though their venturing did not come to the attention of the local newspapers, the diary kept by one of them, A. Bart Henderson, contains the best account of the area to come out of the era of the prospectors.  This party entered what is now Yellowstone Park at its southeast corner after coming up Snake River and over Two Ocean Pass, as the trappers had earlier.
[p. 76] Aug. 30th 1867. It was from this camp [near Bridger Lake] that we first looked upon the far-famed Yellowstone Lake, about 15 miles northwest.
We were at a very great loss to know what it was. Capt. Bracey said he would soon settle that question & let us know the facts. He soon had Capt DeLacys map spread on the grass, tracing out the different rivers that he found marked on the map. 
The Yellowstone Lake he soon found to be 15 miles long & 5 miles wide. This was all contrary to what we could see with our own eyes . . .
However we all concluded that we was on the Yellow Stone, & in sight of the famous lake.
Henderson’s party moved northward to Yellowstone Lake, where they came upon a lone Englishman—Jack Jones, called by them “John Bull”—who was traveling afoot through the wilderness. He was taken with them as they moved down the eastern shore of the lake. While camped at Sedge Creek, the party made two interesting discoveries: the parasitic worms (Bulbodacnitis scotti) which they found infesting many of the lake trout, and the wave-formed stones they thought to be relics of the Aztec Indians. The Washburn party gave the name “Curiosity Point” to the beach where the latter were found.
A less agreeable discovery, on the following day, of “about 80 barefooted tracks, fresh made” (presumably by Blackfoot Indians), caused the Henderson party to change course abruptly by swimming Yellowstone River a short distance above its Upper Fall. While their supplies and equipage were drying in the sun, Henderson went to view the falls, an experience he described in these words:
I was very much surprised to see the water disappear from sight. [p. 80] I walked out on a rock & made two steps at the same time, one forward, the other backward, for I had unawares as it were, looked down into the depths or bowels of the earth, into which the Yellow plunged as if to cool the infernal region that lay under all this wonderful country of lava & boiling springs. The water fell several feet, struck a reef of rock that projected further than the main rock above. This reef caused the water to fall the remainder of the way in spray. We judged the falls to be 80 or 90 feet high, perhaps higher [Upper Fall is 109 feet].
From the falls of the Yellowstone, Henderson’s party crossed the Washburn Range on a dim Indian trail to Tower Fall,  which was recognized by Henderson as “the most beautiful falls I ever saw.” Henderson commented on other important features as his party continued down the river to Emigrant Gulch.
The Yellowstone region was well enough known by the close of 1867 that at least one frontier journalist was led to prophesy its future. Called “a correspondent of the Frontier Index,” but probably editor Legh Freeman himself,  an informant writes as follows concerning the country at the headwaters of the Yellowstone:
Two main forks of the Yellowstone—one heading opposite Wind and Green rivers, and the other opposite Henry’s Fork of Snake river, in the same vicinity that the Madison and Gallatin rise—empty into the big lake which has for its outlet the Yellowstone river, and just below the lake the whole river falls over the face of a mountain thousands of feet, the spray rising several hundred. A pebble was timed by a watch in dropping from an overhanging crag of one perpendicular fall, and is said to have required eleven and a half seconds to strike the river below. That beat Niagara Falls all “hollow”. The river at these greatest falls is represented to be half as large as the Missouri at Omaha, and as clear as crystal. The great lake, like all others in these mountains, is thick with salmon trout of from five to forty pounds weight, and where the milky boiling mineral waters from the star bolt geysers intermingle with the pure, clear water from the running streams, elegant fish can be forked up by the boat load. A few years more and the U.P. Railroad will bring thousands of pleasure-seekers, sight-seers, and invalids from every part of the globe, to see this land of surpassing wonders. 
While the foregoing account contains some blatant exaggerations, it was at least founded upon truth, and that could not be said of another news item which appeared at nearly the same time. According to this story, which was reprinted from an eastern paper,
Mr. Edward Parsons, just returned from Montana, tells the editor of the Leavenworth Commercial a marvelous story. Last July, himself and four companions, while exploring the headwaters of the Yellowstone, came upon an Indian mound, surmounted by a huge stone. Dislodging this stone and several others, they found themselves in an Indian catacomb, containing the skeletons of thirty warriors. Lying beside the bones were numerous ornaments, among them many twisted circlets of gold. Some of these were of unusual size, weighing one and a half to two pounds. What chiefly attracted attention was a massive basin or kettle that occupied the centre of the apartment. This massive article proved to be pure gold, and was so heavy that the party had great difficulty in removing it from its resting place and bringing it into the upper air. The adventurers were enabled, by means of their axes, to sever the mass into portable pieces, laden with which, the party turned their steps homeward, having themselves to walk the greater part of the way, to give relief to their burdened animals. The whole amount of gold was brought to Helena, and Mr. Edward Parsons calculated that his share of the treasure amounted to about $21,000, the whole bulk being at least $100,000 in value. 
In 1868, Legh Freeman continued to publish stories and items about the Yellowstone region. However, his verities were so often obscured by Munchausen details that the effect was to discredit the area’s wonders rather than to expose them. The wildest of these tales was his “Greatest Bear Story Yet”—an outrageous distortion of known facts and current tall tales, of which the following are examples: 
I looked up the petrified tree, and out on a petrified limb saw a petrified bird singing; a petrified song sticking out his mouth about ten petrified feet. Looking down, I saw that the ground was covered with petrified balls like sycamore balls, and from these a considerable forest was growing up and stretching away to the east.
This is the largest and strangest mountain lake in the world. It being sixty by twenty-five miles in size and surrounded by all manner of large game, including an occasional white buffalo, that is seen to rush down the perpetual snowy peaks that tower above, and plunge up to its sides into the water. It is filled with fish half as large as a man, some of which have a mouth and horns and skin like a catfish and legs like a lizzard. This cross range backs up the waters from the head tributaries of the Yellowstone, and thus the lake is formed; and where the water of the lake breaks over the northern face of this cross ridge, there is a perpendicular fall of fifteen hundred feet over one cliff, which is by far the highest fall of any large river, and considering the surrounding scenery, is the most sublime spot on earth.
The foregoing, with the remainder of Freeman’s article, could be consigned to oblivion except that it was so widely read and so influential in creating that reputation for “indulging in flights of fancy when recounting their adventures” with which the prospectors were generally branded. Freeman was almost factual in a later issue, where he compared certain areas of the Sierra Nevada Range with the “Yellowstone Hell,”  and less-so, still later, when describing Yellowstone Lake as “so clear and so deep, that by looking into it you can see them making tea in China.”  Just before an enraged mob put The Frontier Index out of business by burning its boxcar-office during a riot at Green River City, Wyo., Freeman published a last comment on the Yellowstone region, repeating his prophesy of a year earlier. This followed a reprint of a description of the American Falls, on Snake River, published earlier in the Idaho Statesman, concerning which he remarked:
Ha! Mr. Statesman, you should pass over the divide from the head of Snake river and go through the great volcanic region about the Yellowstone lake, on down to the great Yellowstone Falls, fifteen miles below the lower neck of the lake and view a crystal stream as large as Snake river, as it falls over one perpendicular precipice, where we threw down a pine log, which was 11 1/2 seconds striking the river below. Make your own calculations for rates of velocity of falling bodies and see if the Yellowstone Falls are not about six times as great as Niagara. How are your Shoshone Falls? We will show you a summer resort on the Yellowstone in a few years, at which the gentry of all nations will be recreating. 
The era of the prospector extends through 1870, when gold was discovered at the head of the Clark Fork of the Yellowstone (the area around present Cooke City, Mont.). The party which made that strike included A. Bart Henderson, whose diary records the appearance of several place names, and a brief fight with Indians, during their wanderings in the northern and eastern reaches of the present park. Descending Hell Roaring Creek, they turned eastward across the Buffalo Plateau, which received its name from them.
Wyoming Territory, June 21, 1870. Clear & warm. Raised camp early. Followed down the stream east. Here the hills come down on both sides forming a very rough cañon. We turned to the left, crossed a low divide or gap, & came to a beautiful flat, which we gave the name of Buffalo Flat [Buffalo Plateau], as we found thousands of buffalo quietly grazing. This flat is something like 10 miles by 6, with numerous lakes scattered over it, & the finest range in the world. Here we found all manner of wild game—buffalo, elk, blacktail deer, bear & moose. Camped here. 
From Buffalo Plateau this party moved north and east, investigating the headwaters of Buffalo and Slough Creeks (discovering both gold and grizzly bears at Lake Abundance) before descending to Clark Fork River. There they made the strike which developed into the New World Mining District, though they did no more than prospect at that time. Instead of settling down, those restless men crossed the mountains south of Pilot and Index Peaks, hoping to do even better. Their odyssey is recorded thus by Henderson:
[p. 92] 22nd [July, 1870] Clear & cold. Raised camp early. Traveled south, came down on a very rough stream [Cache Creek], high lava peaks on both sides. The country soon changes to open rolling hills [with] fine grass [and] game trails running in all directions. Here we camped at the forks for the purpose of prospecting.  Found no gold. This days travel was south, thro buffalo, elk & bear—all very tame.
23rd Cloudy & cold. Raised camp early [and] followed down [p. 93] creek in south direction. 8 miles below came to open country on the East Fork [Lamar River] of the Yellowstone.
Here we found thousands of hot or boiling springs.  Camped on East Fork, south side. Just opposite camp a small creek empties into river. One mile up this creek is a very singular butte, some 40 feet high, which has been formed by soda water. We gave the cone the name of Soda butte, & the creek the name of Soda Butte Creek.
The prospectors then descended Lamar River to its mouth, doubled back along the Specimen Ridge-Amethyst Mountain divide to Flint Creek, where they descended to Lamar River again. They then moved up that stream to the Little Lamar River, which was ascended to the high country between the drainages of Lamar River, Sunlight Creek, and the North Fork of Shoshone River. It was there, just as they had reached what they recognized as mining country (later the Sunlight Mining District), that they were attacked by Indians who made off with their animals.  The result was the abandonment of most of their outfit and a retreat across the northeast corner of the present park toward succor at the Crow Agency (Fort Parker, near present Livingston, Mont.). Their escape was a harrowing experience made worse by dissension, an attack by wolves at the mouth of Miller Creek,  and another brush with Indians wherein they followed the rule of “shoot first and ask questions later.” 
A story which appeared in the Helena Daily Herald that summer, though a complete phony both in its description of Yellowstone geography and in the central event—the supposed death of 18 Indians at the Falls of the Yellowstone —does expose an attitude which was, by then, common among the prospectors. Despite the fact that Crows killed Crandall and Daugherty, and Arapahos were behind the attack on the Henderson party (this according to James Gourley), the inoffensive “sheep-eater” residents of the Yellowstone region tended to get the blame, and nowhere is this more obvious than in Sunderlee’s statement:
We felt no great uneasiness however, knowing full well that with our improved firearms, we would be enabled to overcome fifty of the sneaking red devils. It is proper here to add, that the “Sheep Eaters” are those of the Snake and Bannack tribes, who would not live with their brethern in peace with the whites; but who prefer living remote from all Indians, and civilized beings: foes of their former tribes and of the whites. A body of savages who would gladly welcome death in preference to capture, either by the white man or red man; hated and hunted by their former associates, they are compelled to seek asylum in the mountains, where it is so sterile that no game but the wild sheep abound. Here they exist as best they can, which is but little removed from starvation.
That was not true in any respect, but it was so generally believed as to constitute a very real danger for the Shoshoni-Bannock “sheep-eaters” who were living in the Yellowstone region in the old way of pre-horse days. Thus, they willingly accepted Chief Washakie’s invitation to join his Shoshonis on the Wind River Reservation in 1871, and abandoned their Yellowstone home forever.
The body of knowledge concerning the Yellowstone region made available by the explorers, trappers, and prospectors of this period, though extensive, was yet fragmentary and often contradictory, and it did not constitute a comprehensive view of the Yellowstone region and its wonders. Such a picture of the area only materialized out of definitive exploration.