Popular Science Monthly/Volume 55/July 1899/Geology of the Klondike Gold Fields
|GEOLOGY OF THE KLONDIKE GOLD FIELDS.|
LATE PROFESSOR OF GEOLOGY AT THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA, FELLOW OF THE ROYAL GEOGRAPHICAL SOCIETY OF LONDON.
THE gold fields of the Klondike or Troandik district, as officially designated, lie along or immediately about the waters, whether direct or tributary, of the Klondike, an eastern affluent of the Yukon, which discharges into the "father of northern waters" at the site of Dawson. The Klondike itself, whose upper waters are as yet only imperfectly known, seemingly carries but little gold, the main quantity of the precious metal and that which has made the region famous being contributed by one of its southern arms, the Bonanza, and by a tributary of this, the Eldorado. Hunker Creek, draining a mountainous district several miles to the eastward of the Bonanza, and like it a southern affluent of the Klondike, finds promise of a wealth but little if at all inferior to that of the Bonanza. In a broader or more popular sense, the Klondike region not only embraces the special district so designated in the books of the Gold Commissioner, but also the entire tract which heads up to the sources of the streams that have before been mentioned, and thereby, with Quartz, Sulphur, and Dominion Creeks as tributaries of Indian River, takes in the greater portion of the Indian River mining district, and with Baker, Reindeer, and other creeks on the west, the official districts indicated by these names as well. With this limitation the region roughly defines an area about forty miles square, whose northern boundary lies somewhat to the north of the sixty-fourth parallel of latitude, and on the west reaches to within about thirty-five miles of the international boundary, the one hundred and forty-first meridian of west longitude.
This area of approximately fifteen hundred square miles, which but little exceeds that of Rhode Island or of the county of Cornwall in England, may be broadly characterized as being gently mountainous, with elevations of five hundred to fifteen hundred feet, and in the highest parts of about twenty-two hundred feet. Its lowest depression is the valley of the Yukon, which, in itself occupying a position about fourteen hundred feet above the sea, gives to these points absolute elevations of three and nearly four thousand feet. Dome Mountain, or, as it is frequently designated, simply "The Dome," and less often "Solomon's Dome," "King Dome," and "Mount Ophir," appears to be the culminating point of the entire region; and its prominent position at the water parting of Bonanza, Hunker, Sulphur, and Dominion Creeks makes it a noble figure in the landscape, and the most interesting single feature to the prospector and miner. No absolute determinations for altitude have as yet been made for it, but when crossing the summit it seemed to me that it could not be much under four thousand feet, and I believe that Mr. Ogilvie gives to it about thirty-five hundred feet. The landscape which this mountain dominates is surpassingly beautiful, and I know of no finer view from similarly low mountains than that which this one commands. The sharply incised wooded valleys of the different streams that head up to it tear the mountain into projecting buttresses, and in the ridge that leads off from it southwestward contracts it to the extent of forming for half a mile or more a narrow backbone or saddle. In this respect it reminded me much of Mount Katahdin, in Maine. On a clear day the distant main mass of the snow-capped Rocky Mountains is sharply outlined against the northeastern sky, a most impressive setting to the verdant slopes that trend off toward it, only to disappear in the belt of plain that separates the two mountain systems. I was unfortunate in not getting the full benefit of this view, as at the time of my first crossing the atmosphere was very cloudy, and on the second it was so surcharged with smoke from forest fires in the valleys of Gold Bottom, Quartz, and Sulphur Creeks that hardly more than the foreground was visible.
A succession of five or six knobs runs out from the ridge to which reference has been made and which trends off in the direction of the head waters of Eldorado, and these, together with the main Dome, are sometimes spoken of as the "Seven Domes," but they have no particular significance in the orographic detail and can not even be said to be clearly defined to the eye. Dome Mountain is held in a respect bordering almost on veneration by the Klondikers, inasmuch as it is generally thought to be the mainspring of the gold supply which is contained in the streams that fall off from it, and this means nearly all the good and the promising streams of the entire region. And, in truth, there is for the moment no way of absolutely disposing of the miner's suppositions, nor can the circumstance that little or no gold has yet been found in place either on or in the mountain be given much value in the discussion of the probable origin of the gold, inasmuch as the same negative condition
confronts us in a study of the rocks of all other parts of the same and adjoining regions. Assuming that alluvial gold is in the main a derivative from reef gold, it is certainly strange that streams flowing in well-nigh opposite directions, and yet rising within very short distances of one another, should be so largely charged with gold, unless they have obtained it from a common source; nor can the fact, as received and reported by most miners, but of the full import of which I have not yet fully made up my mind, that the different streams carry different classes of gold, be argued away as having no significance in this connection. Claim holders profess at most times to be able to distinguish between Eldorado gold and that of Bonanza, between the gold of Bonanza and that of Hunker or Dominion, and so on; and there is no question that marked differences in color and in the contours of the coarse flakes and nuggets do present themselves, and even in narrower limits than has here been outlined. Thus, the gold from French Hill, abreast of Claim 17 on Eldorado, has a distinctiveness that is largely its own, and hardly follows the gold of the rest of the Eldorado tract; and the same is true of the gold of Skookum Hill in its relations to that of Bonanza, and also of that of Victoria Gulch. Moreover, the recent assays that have been made by the Bank of British North America and the Canadian Bank of Commerce, in Dawson, of the gold of the different creeks and gulches show plainly that marked differences as to fineness are distinctive qualities—at least they appear to be such at the present time. Thus, while Eldorado and Bonanza gold generally assays but about $15.50 or $15.80 to the ounce. Dominion gold shows as high as $17.80, and Hunker close to $18.50; the gold of Bear Creek, a minor tributary of the Klondike, is reported to actually give $19.20 to the ounce, falling only behind the almost pure specimens that have been reported from American Creek and Mynook, and to which a Valuation of nearly $20 has been given. If these assumed facts continue to be proved true, then they must argue in favor of a distribution of gold from largely localized spots or areas, a conclusion that is also pointed to by a number of other circumstances. On the other hand, there are some facts which point in quite the opposite direction, and some of these will be referred to later on.
None of the mountains of the region even approximates the snow line, which would here probably occupy a position not much below six thousand feet, and on the northern face perhaps even rise to seven thousand feet. Not a vestige of snow was seen by me when crossing the Dome, not even in the most sheltered hollows, a condition that at first strikes one as strange, considering that in so many parts of our own mountains of equal or less elevation snow may be found lingering through a long period of the summer months. But here the greatly protracted hours of summer daylight and heat, together with the correspondingly diminished period of night, when a regelation might take place or melting at least could be arrested, have a marked influence in dissipating the winter's snows and ice when these are not particularly heavy, I did not find the August heat quite so intense on the mountain tops as I had been led to
suppose that it would be, but there was quite enough of it to satisfy an ample vegetation and to make heavy garments in walking more than a luxury. Unfortunately, my thermometer was away from me at this time, and as sensation in this dry northern climate is so difficult to gauge by the standard of the mercurial index. I shall not hazard a guess as to the actual reading.
Taking the mountains in their entirety, it is difficult from single points of view to determine for them any definite relation. There are so many valleys in close proximity to one another, some very ancient and others relatively modern, and with trends so opposed in all directions, that in the absence of a dominant ridge or mass this relation becomes very confused; and I was not in a position, with the limited time at my command and the deficiency of rock outcrops, to positively define any main line or axis of uplifts. Yet I suspect that there is one such, with a generally east and west bearing, whose trend might correspond with that of the ridge already referred to, which, with a southwesterly deflection, unites Dome Mountain with the mass that separates the upper Eldorado from Chief Gulch. What strikes one as particularly interesting in the conformation of some of these mountains when seen from an elevation is their hummocky appearance. This is particularly noticeable in the mountains which close in the Eldorado and Bonanza Valleys. With considerable actual elevations, they convey the impression of being merely swells or undulations of an open surface, very much like magnified morainic knolls in a glaciated country. This depressed type of mountain structure, with the evidence of its expanded valleys and gently flowing contours, carries with it the proof of long-continued degradation, and of a history whose pages read far back into geological chronology.
With the evidences of antiquity before us, there are yet indications, amounting, it seems to me, almost to proof, that many of the more pronounced features of the region date their origin from only a comparatively recent period. Such is the case with a number of valleys that are tributary to the main ones, and even the latter appear to have been modified by late stream displacements. Taking the Eldorado or Bonanza, with their open U-shaped troughs and in most parts gently sloping banks, as types of the older valleys, it is surprising to note how many of their tributaries have the deeply incised and narrow contours; and I am led almost to conclude that some of these are really of very late construction. The stream displacements, which, by reason of the indices they give to the finding of new placers, are now beginning to be so attentively studied by the miner and prospector, are emphatic in their testimony in this direction. One has but to note the triangular area that is included between Trench Gulch (tributary to Eldorado abreast of Claims 17 and 18) and Adams Creek (tributary to Bonanza at Claim 6 below Discovery) to be convinced of the actuality of recent transformations. Most of the miners regard the high-level gravels of this tract—of French Hill, Gold Hill (opposite to Grand Forks Village), Skookum Hill, and Adams Hill—so rich in gold as to make the claims fairly the rivals of the creek claims, as representing the ancient high-level flow of the Eldorado and Bonanza, but I am convinced that this is not the case (although it is certain that both streams mentioned did at one time flow at as high, and even considerably higher, levels). The materials that so largely distinguish these bench or hillside gravels (placers) are in greater part rounded bowlders or cobbles of white quartz, with a marked deficiency of the fragmented schists and slates which make pay dirt and bed rock in the course of the streams below.
Per contra, the creek claims of Eldorado and Bonanza contain, as a rule, only an insignificant quantity of the rounded quartz bowlders, while almost everywhere where excavations have been made the body and substance of the output are the flattened and discoid parts of the mother-rock of most of the region—quartzitic, micaceous, hornblendic, and chloritic schists, and with them a less quantity of gneissic and dioritic rock. The high quartz-capped knob to which reference has already been made as marking the water parting of French, Nine Mile, and Adams Creeks, has large quartz masses entering into its composition, whether as bosses, dikes, or veins, and to them, or rather their wasted parts, must we look for the source which has so generously supplied the materials of the French-Adams Hills benches. There has been a bad break-up in this quarter, and the materials resulting from it have been swept into the confluence (delta) of the two streams which define the main valleys. Furthermore, the descending arcuate contour lines which are so well marked by terrace slopes on that face of French Hill which is turned to the corner of Eldorado and French Gulch, show plainly the receding course, in the direction of south, of French Creek (Gulch). On the hill slopes south of the position which it now occupies there is none of that deposit which lies to the north of it; the riches of French Hill are delimited by French Gulch, and even in the gulch itself there is nothing that can be compared with what is found on the heights. Again, on the side of Eldorado opposite to French and Gold Hills there is the same deficiency as regards the characteristic bench deposits, and this also holds true with the Bonanza opposite Skookum and Adams Hills. If these high-level deposits were in fact the ancient waste of the Eldorado and Bonanza, we should naturally expect to find at least "outliers" on the less favored bank of the streams, and surely in the case of the Eldorado former evidence of this deposition ought to be had on the
hillsides, similarly contoured to those of the north, which lie south of and immediately adjoining French Gulch.
Through virtually the entire Klondike tract and far beyond it on all sides there are evidences of high water flows. No more perfect presentation of high-level terraces can be had than that which defines the first line of heights, of perhaps one hundred and fifty to two hundred feet, which so beautifully impress the landscape of the Yukon about Dawson. The observer, from a still loftier elevation, notes these flat-topped banks, having the regularity of railroad constructions, following the course of the river as far as the eye can reach, here perhaps interrupted by a too steeply washed buttress, elsewhere washed to low level by some stream which has taken a transverse direction. A somewhat higher line of benches curves around the still higher points of eminence, and defines the course of water across country—such, at least, it is to-day. And all the way to the top, scattered evidences of the recent presence of water can still be found. I met with rolled or water-worn pebbles so near to the top (the actual summit and not the position of the signal flag) of the high peak overlooking Dawson that it may safely be assumed that they also occur on the very apex (about eleven hundred feet above the present level of the Yukon), a conclusion which is more than strengthened by the finding of pebbles at even a greater elevation on the French-Adams Creek knob. While thus presenting the evidence of high water levels, I am far from convinced that this evidence points exclusively to river flows. Much more does it appear that, in one part of its history at least, we are dealing with the evidences of the past existence of large lakelike bodies of water, perhaps even of a vast inland sea. The contours of the country in a sort of ill-defined way suggest this interpretation—an interpretation that is not, however, without evidence to support it, and which seems also to have been entertained before me by McConnell and by Israel Russell. The latter investigator has, indeed, given the name of Lake Yukon to a former extensive body of water, of which the existing Lakes Lebarge, Marsh, Tagish, and Bennett, with the connecting Yukon, are only dissociated parts. This lake is assumed to have been about one hundred and fifty miles in length, with a surface elevated between twenty-five hundred and twenty-seven hundred feet above the sea.
First in the line of evidence may perhaps be taken the universality of wash gravel and of terrace débris and the great heights which they occupy. While I have not myself observed such evidences of water action on the very summit of the Dome, there is reason to believe that they do or at least did exist. Most of this summit, in its narrowed form and rapidly descending slopes, has been, if one may use the expression, more than washed off, and could hardly be expected to retain for any great length of time accumulations of loose fragmental material. But at least its far-off continuation near the source (right fork) of Eldorado Creek bears some of it on its shoulder, and I have also seen it in an excavation on the loftily located Claim 71 of that stream. Nearly abreast of the international boundary, the one hundred and forty-first meridian of west longitude (Greenwich), McConnell and Russell noted the terrace line of the Yukon River as high up as seven hundred and thirty feet, which is still about four hundred feet below the point where I obtained wash gravel on the peak back of Dawson; but Dr. George Dawson found the terraces on Dease Lake to rise to thirty-six hundred and sixty feet, and elsewhere he calls attention to having come across water-rolled gravel at an elevation of forty-three hundred feet, which would probably exceed by about six hundred feet the culminating point of Dome Mountain. Such high water could, with the existing configuration of the land surface, hardly define any other feature than that of a large interior sea or of a series of lake basins; and while it may be argued that there has been sufficient degradation of the land surface since the period of the height of water to permit us to reconstruct a contour that would be in harmony with altered and reduced river courses, and relieve us from the necessity of invoking the assistance of lacustrine bodies in a solution of the problem, it does not seem to me likely that this has been the case. The physiognomy of the upper Yukon Valley supports this contention, and even to-day the river has not yet fully escaped from a lacustrine condition which is merely fragmental of a previous state.
On one point bearing upon the succession of events in the upper Yukon Valley, and which has its connection with the history of the Klondike region, my conclusions differ somewhat from those that have been expressed by Dawson. This pertains to the deposit of volcanic ash which is so marked a feature of the accumulations of the river's banks. For nearly three hundred miles by the course of the river a stratum of pumiceous ash, ordinarily not more than four or six inches in thickness, constitutes almost without break the top layer but one of the banks on either side, and that which is above it is generally only the insignificant soil or subsoil which immediately supports the vegetation. So persistent is this ash layer, and so uniformly does it hold to an even thickness and to its exact position beneath the surface, that without further examination one would be tempted to believe from a little distance that it was merely the ordinary subsoil layer from which the color had been leached out by vegetable growths. Here and there, where there have been local disturbances or water washings have produced concentration, it may have acquired a development of a few feet, and occasionally it has accommodated itself to flexures or saggings of the deposits which it normally caps as a horizontal zone. Dr. Dawson, in commenting upon its occurrence, correctly assumes that it represents one continuous volcanic eruption, the date of which might fall well within a period of a few hundred years, and he speculates as to its being possibly associated with an outbreak from Mount Wrangel or some active cone which is represented by the Indians to exist in the region of the upper White River. Beyond this, from the normality of its position, and the assumed fact that no fluviatile or aqueous deposits have been found overlying it, the same observer argues that the outbreak must have taken place subsequent to the formation of the present river courses and their valleys, a conclusion in which I do not see my way to concur. The only satisfactory interpretation of this vast uniformly placed and uniformly layered deposit of ash is to me that which assumes a deposition in a widely extended lake basin, or in shallow lagoon waters which already in part occupied the present valley surfaces. In such waters precipitation from long-continued suspension would proceed gradually and evenly, to the end of shaping a deposit of nearly uniform development and of vast extent. Such depositions we find in the valleys lying north of the City of Mexico (Zumpaugo, Tequixquiac) and in the lacustrine area of Anahuac, also in the famous fossiliferous basin of Florissant, in Colorado. With the subsequent formation or reformation of the river's course we should have this deposit cut through, with the result of presenting the even layer which is so persistent in its following. This method would also account for the anomalous position in which we find the ash deposits; while still holding the same relation to the top surface, it occasionally rises far above what might be assumed to be its normal height or level above the water's surface—from four to ten feet—a condition that would hardly be in consonance with the assumption that the ash was deposited after the actual river channels had been cut. But other and more direct proof of aqueous occupation after the laying of the ash is had in the fact that in one place at least, and doubtless many more such will be found on closer investigation, lacustrine or fluviatile shells (subfossils) occur in the layer overlying the ash. A locality of this kind is found on the right bank not many miles above the Five Finger Rapids. Here, at a height of not more than four feet above the river, I had the pleasure of determining species of L'imnea and Physa, associated singularly enough with Helix, in the layers immediately above and below the ash bed, and in both horizons the species were identical. This isolated fact speaks volumes for itself. Had this been the region of Helena, Ark., I should have been prompted to class the bed with a portion of the Mississippi loess. What interested me further in this connection was the fact that up to this time I had failed to bring to light one solitary mollusk from the upper Yukon, and to all inquiries regarding the existence of shellfish in this northern water invariably a negative reply was received. Only on that day did I again obtain success
in my malacological effort, the almost icy waters rewarding my search with a single specimen—unfortunately subsequently lost—of a Bythinella, or some closely related type, so that even to-day my knowledge does not permit me to state if the subfossil species of the banks have their living representatives, either specific or generic, in the almost wholly noncalcareous waters of the existing river. The question from more points than one is interesting, and deserves more than passing attention. It may be remarked in this place that the only other fluviatile invertebrate which I found in these waters was a white siliceous coating sponge, whose statoblasts were well visible to the naked eye. Unfortunately, the loss of my specimens has prevented determination, a circumstance the more to be deplored as these fresh-water sponges are the most northern in habit known to the zoölogist.There is evidence of another kind pointing to a comparative newness of much of the present course of the Yukon. The feature has been noticed alike by nongeographers and geographers, and by geologists as well, that the arm which carries the greatest volume of water does not everywhere occupy the main orographic valley. Thus, as Dawson has well pointed out, in coming up the stream the valley of the Big Salmon appears to be more nearly the continuation of the main valley below than that which still (and properly) continues to be designated the Lewes (Yukon) above; and this is still more markedly the case with the Hootalinqua (Teslin-too or Newberry River) at the confluence with the Thirty Mile. Even the valley of the Pelly at its junction with the Yukon, near Fort Selkirk, would perhapS to most persons suggest itself as the main channel of erosion. There is no hardship to geological facts in invoking the aid of great displacements to account for a condition which to my mind is well impressed upon the landscape; for, even without the proper or fully satisfactory evidence in hand to support the view, I fully believe that the greater part of the upper Yukon tract only recently emerged from a lacustrine condition. Nor is it to me by any means certain that this emergence or final reconstruction of the land surface into valley tracts need be more than a few hundred years old, or necessarily older than the deposition of the volcanic ash, which is hypothetically carried back to Dawson to a possible five hundred years or so. If it should be objected that we know of no such rapid change in the configuration of a land surface brought about by aqueous agencies, it might be answered that the mechanics of erosion in a pre-eminently drift-covered region, under subarctic conditions and with the influence of a most powerful and energetic stream near by, have neither been studied nor observed.
Let us examine the possibilities of the case. As an initiatory premise it might be assumed, without much chance of either affirmation or denial, that the degradation of the land surface in the immediate valleys of the main streams is or has been in the past taking place at the rate of half a line per day; so far as the eye and ordinary instruments of measurement are concerned this is a quite inappreciable amount, and I see no reason why it may not be assumed as the working power of the Yukon. With this rate of erosion a valley trough or contour of about a foot and a third might be formed in the period of a single year, or of nearly seven hundred feet in five hundred years; and if we lessen the daily erosion to one quarter of the amount stated—i.e., to an eighth of a line—we should still have in this same period of five hundred years, speaking broadly, a trough of about one hundred and seventy-five feet depth, quite sufficient to have brought about most marked changes in the aspect of a drift-covered lagoon region, and perhaps ample to account for those physiognomic peculiarities which have been discovered. I am fully impressed with the magnitude of the distance which separates the amount of erosion which I have assumed—an eighth of a line daily—from the "one foot in six thousand years," which has been preached categorically from lecturn and text-book for the better part of a quarter of a century and threatens to make dogma for still another period of equal length; but the conditions here are entirely different from those of average continental denudation—in fact, have as nearly nothing in common as they can have. My observations in the tropics and subtropics have most impressively taught me the lesson of rapid changes, and with the conditions that are and have been associated with the Yukon, I am prepared for the lesson of equal change in the north. But, as a matter of fact, are we not taught of a removal in the west central United States of some twelve thousand feet of rock strata in a period not impossibly considerably less than two hundred thousand years? The one foot in sixteen years has here likewise nothing in common with the "prevailing" rate of continental destruction.
While stalled on a bar on the Yukon River, about two miles above Fort Selkirk, I was much impressed with the mechanical work of the stream. The gravel and pebbles were being hurried along rapidly under the lash of a five to six mile current, and their groans were audible frequently when they themselves were invisible. Every few minutes our steamer would swerve from her seemingly fixed position by the undercutting of the bar, and perhaps it would be not far from the truth in saying that we should be to-day in very nearly the same position that we were in then had it not been for this undermining action of the stream. Let it be remembered that the Yukon has a current ranging up to seven miles, or to eight, as some of the navigators say, and that in certain months it is swiftly ice-bound both on top and at the bottom, and heavily charged with bowlders, and one may well realize the work of which it is capable. That with which I have debited it is purely hypothetical or conjectural, but it may serve a purpose in the elucidation of the main problem.
In its more distinctively geological relations the Klondike region may be broadly defined as one composed in the main of schists and schistose rocks, defining an area of considerable disturbance. Owing to the limited number of outcrops, by far the greater part of the surface being still buried beneath vegetation of one kind or another, the variety of rocks included within the region can best be told from an examination of creek bowlders or the different dumps that mark hundreds of diggings and prospect holes along the various valleys and gulches. Some of this output in which may be found fragments of quartz and quartzitic schist, of mica, hornblende, and chloritic schists and slates, of granitic gneiss and gneissose granite, porphyry, diabase, diorite, and quartz (quartzite), is probably extra-territorial, having been washed in at a time when a more extensive foreign water had access to the region; but there is enough of outcrop to show that most, and perhaps all, of the types here indicated are really a part of the tract. The schists and schistose rocks, whose age from direct evidence in the field I was unable to determine, but which are almost certainly the equivalents in greater part of the Birch Creek series, as described by Spurr from the American side (Birch Creek and Forty Mile districts), constitute the kernel of the region. Observation is as yet too limited to permit of a positive classification of these schists according to their natural relations, and the reasons that have prompted some to consider them as being in part of pre-Paleozoic age are not quite clear to me, although they may easily be such. Of granite and true gneiss in position I saw practically nothing, and the limestones and marble were not sufficient in quantity to permit me to identify the heavy beds which are considered to be the distinguishing element of the Forty Mile series. The beds where exposed show in most parts steep dips—in places standing almost vertically—but in how far these dips are uniform or the reverse, or in any way define a line of strike with anticlinals and synclinals, must be left for future close examination to ascertain.
Great lumps of white or pinkish quartz, some of them in situ, others washed or rolled down the open slopes, occur at many pointsof some of the mountain elevations, indicating the presence of dikes
and gash veins, and in part of interstratified beds containing this material. I found much of it at several "horizons" of the slope back of French Hill, and also as a cap overlying the badly cleaved and fragmented schists of the summit (three thousand feet?) of the prominent knob which dominates this region. The same type of "kidney" quartz appears at repeated intervals on the slope leading up to the Dome, almost immediately after leaving the junction of Carmack's Fork with the Bonanza, and also on the saddle ridge which might properly be considered to be a part of the summit of Dome Mountain. Prospectors have in nearly all cases staked these assumed outcrops of quartz, recognizing them as ledges, and in a number of them have claimed the discovery of the "mother lode." So far as visible gold is concerned, I have in nearly all cases found them to be absolutely barren, and I do not think at this time that there is much chance of finding anything materially valuable in them, although events might prove the reverse. Most of the quartz that has so far been discovered in direct association with the gold—that is to say, wrapped up with or within itself, as in the case of the quartz-gold nuggets of French Hill—is of a gray-blue or pinkish tint and of a granular and nonspathic type, therefore differing materially in aspect and structure from the quartz of the hillsides and from the greater number of the quartz bowlders that are contained in the dumps or have been removed from bed rock. Some of the bowlders or rolled pebbles containing coarse gold are of the same character of quartz as the quartz of the hillsides. Notably one such was shown to me as coming from a high-bench claim (Millett's) on Adams Hill (left "limit" [bank] of Bonanza, between Little Skookum and Adams Creek), and other similar fragments taken from the rock in situ were observed on Gay Gulch and the ridge which separates the head waters of this stream from those of Eldorado. In a dump at the mouth of Gay Gulch (a right-hand tributary of Eldorado abreast of Claim 37) I found fragments of rotted quartz which were well sprinkled with fine gold.
It does not by any means appear so conclusive to me as seemingly it does to Professor Spurr that because in some gulches the gold heads up in increasing quantities the nearer we approach the beginnings (heads) of these gulches, and that with this approach the coarseness of the grains and nuggets likewise increases, we are necessarily forced to assume that the travel of the gold at large has been confined within the boundaries of the gulches in which it is at present contained, or that its source is to be sought near by. A number of the most "solid" streams of the Klondike region, such as the Bonanza and Eldorado, if we are permitted to judge from the evidence of outputs and of prospects up to the present time, hardly sustain the conditions of the American creeks. The richest claims on the Eldorado are, starting from its mouth—the junction of the Bonanza—4, 5, 12, 13, 29, 30, 31, 36, with other claims abundantly rich between these. Number 30 is, I believe, generally considered to be the banner claim, and it is situated about three miles up—far enough, perhaps, to sustain in a superficial way Professor Spurr's generalization as to location—and above it 36 is not unlikely to show up as well as any of the other creek claims below. But the valley of Eldorado, whether constricted or open, continues for miles beyond either of its two head forks—that which is known as Eldorado proper, and the one, Chief, or Chief Isaac Gulch, which is geographically the continuation. So little has been found above 36 or 37 that the stream in that part is ordinarily spoken of as being barren. Again, so far as the tributaries on either side of Eldorado are concerned, and the possibility that they are responsible for the gold that is contained in the main stream between 37 and 1 rather than the Eldorado itself—a condition in no way impossible or improbable—it can only be said for them that up to this time they have, with the possible exception of Oro Grande (tributary to Eldorado abreast of Claim 31), yielded very little gold themselves, and have hardly given indication of containing much of a supply. I have used the words "up to this time" advisedly, because I am aware upon how little the evil reputation of a gulch rests, and how prospectors deceive themselves by the character of their defective prospect holes. Hence, while my argument is drawn from existing evidence, it can not be assumed that this evidence is by any means sufficient to warrant a conclusion. It is by no means unlikely that some of the lateral gulches will really be found to be largely gold-bearing, and of such Gay Gulch and the left-fork ascending of Eldorado (Eldorado proper above 47) appear to me the most promising.
The condition of the Bonanza is very similar to that of the Eldorado. Its greatest wealth, as so far determined, is concentrated in its middle course, beginning about five miles above its mouth and terminating some six miles below its source. But very little gold, if the information given to me is correct, has been taken out from or determined to exist in the tract lying above Claim 42 above Discovery, or the mouth of Victoria Gulch (left-hand tributary, whose source is found on a ridge from the opposite side of which Gay Gulch descends to the Eldorado), and yet the valley continues open and without material change for at least two miles, and with a certain contraction for four miles more. Barring the Eldorado and the streams coming in from the same side nearest to it—Big Skookum, Little Skookum, and Adams—few if any of the side gulches of the Bonanza are known to be really rich in gold, and for the moment, at least, they can hardly be looked upon as having furnished the main supply to the main stream.
- From Alaska and the Klondike. With thirty-five full-page illustrations and three maps. By Prof. Angelo Heilprin. New York: D. Appleton and Company. Pp. 326. Price, $1.75.
- Prof. Israel Russell has made the interesting observation that orographic movement may now be taking place in the region of the middle Yukon, about the Lower Ramparts, with the uplifting of a mountain range athwart the river; on this supposition he seeks an explanation for the detail of the Yukon lowlands.
- Professor Russell, in discussing the flood-plain deposits of the Yukon about the mouth of the Porcupine River, says that "fresh-water shells were frequently observed in the finer deposits." Unfortunately, no statement is made of the types which they represent.
- Since writing the above intelligence has been received of the location of a rich pay streak on Gay Gulch.