

REVIEW AND GENERAL DISCUSSION. 



493 







When the termination here of this series of heavy banks is considered in connection with the 

 additional significant fact that the west branch of El Dorado Canon is stated to have been rich in 

 early days up to a point nearly opposite to the Ayers claim, but not above, it becomes eminently 

 probable, I think, that the stream which accumulated these heavy banks, from which the greater 

 portion of the gold originally found in Ei Dorado Canon seems to have been derived, issued some- 

 where in this immediate vicinity from the ridge on the west, and. here first entered the area now 

 occupied by the modern canon. There is little chance, I think, of its having come from the east or 

 northeast across the present canon instead of from the western side; because no correspondingly 

 heavy banks of gravel have ever been found either in the spurs on the opposite side of this branch 

 of the cation, or anywhere along the eastern branch above the near vicinity of Deadwood. 



The southeasterly direction in which the Mountain Gale channel at Damascus is running, and 

 the northwesterly direction from which the channel at the Dam claim appears to be coming, so far 

 as it has yet been followed, together with the short rectilinear distance between the two localities, 

 might lead one who should judge from the map alone to infer that the Dam claim was on the 

 continuation of the Mountain Gate channel. But I do not think that such can be the fact. 



The relative heights of the two places indeed are such as might permit of it ; though in that 

 case, the distance being some two miles (and probably more than this, as the stream would run), 

 the average grade for the whole distance would be considerably less than the grade of the Moun- 

 tain Gate channel has proven to be for nearly three quarters of a mile from the mouth of the 

 tunnel at Damascus. But the strongest argument against any connection between these two 

 channels? lies in the totally different character of the gravels which fill them. What is the real size 

 of the ci. «nnel at the Dam claim northwest of the " party-tunnel " is not known, as its eastern 

 rim has not been seen. But it is not probably so large as the Mountain Gate channel. 



In any case it is almost impossible to conceive how a channel like that at Damascus could be 

 filled for a distance of at least three quarters of a mile with a gravel so purely quartz, and full of 

 such enormous white boulders of it, and then within the next mile and a half have the character 

 of its gravel so completely changed that quartz should become almost a rarity, more than nine 

 tenths of the boulders being dark-colored metamorphic rocks. 



Nor do I think it probable, either, that the Dam claim has any connection with the "black 

 channels" at Damascus. This, indeed, is possible. But the peculiar "gray cement" of Deadwood 

 is plenty at the Dam claim, while I saw none of it at Damascus ; and furthermore I have an im- 

 pression (although I cannot now find any note of it) that the grade of the black channels at 

 Damascus descends the other way, that is, towards the northwest. 



But if the Mountain Gate channel of Damascus, though running now straight towards the 



Dam claim, does not go there, where then does it go 1 ? I answer that it seems to me the proba- 

 bilities are strong that after holding on for a certain distance farther its present southeasterly 

 course, it will be found to curve to the south and southwest, and continue along under the ridge 

 between the heads of Shirt Tail and the western branch of El Dorado canons, finally breaking out 

 into the latter in the vicinity of Gas Hill, thus proving itself identical with the stream which 

 furnished the gravel along the spurs from there to Michigan Bluff. 



One other item in addition to those already mentioned, which goes to strengthen the probability 

 of this, is the fact that in all the heavy banks along these spurs, as well as at Michigan Bluff 

 itself, the gravel is pretty highly quartziferous, though mingled to a greater or less extent with 

 other matters ; and it is only in the tunnel claims along this part of the ridge that the gravel is 

 generally dark in color and contains but little quartz. 



If this conclusion be correct with reference to the course of the Mountain Gate channel, we thus 

 have, during a large portion at least of the gravel period, a stream of considerable size correspond- 

 ing moderately well with the present El Dorado Canon. Indeed, it is not impossible that this an- 

 cient stream may also have forked at a point not far from where the modern canon does, an easterly 

 branch coming in from the vicinity of Last Chance by way of the northern edge of the Devil's 



Basin and the western side of the ridge at Deadwood. And when we remember that at all three of 



