504 



THE VICINITY OF PLACERVILLE. 











cutting deep enough to take tliem all away, and isolate greater or smaller patches of them here and 

 there, thus giving origin to those curious lenticular masses, like the heavy one of white lava, 

 which has already been entirely washed away in the hydraulic work at Coon Hill. 



The channels so excavated were subsequently filled, either with similar material, or with 

 gravel, or with a different kind of volcanic matter, and so the long work went on. After 

 the white lava had ceased to gather, then came to Placerville the mountain gravel, the streams 

 which brought it excavating also to a greater or less extent their own channels through the 

 previously accumulated matter, gathering their own materials from the dark-colored compact vol- 

 canic rocks, which had made their appearance higher in the mountains, grinding a portion of 

 these materials to powder, rounding and smoothing the rest to a perfect gravel, and picking 

 up occasionally a pebble of quartz or granite or slate by the way, and finally piling up all this 

 stuff, to depths sometimes of a hundred feet. Lastly came the successive deluges of black lava, 

 or volcanic breccias, which overspread the whole, and crown the highest crests of the modern 

 hills and ridges. 



■ 



Such seems to be the outline of the most prominent features in the history of the gravel hills of 

 Placerville. The vast complexity of their detail forms a labyrinth whose windings it is hopeless 

 to expect will ever be completely traced, and whose history, if fully known, it would probably 

 require many a ponderous volume to relate. 



Yet the general modus operandi of their formation seems evident ; the order of succession of the 

 leading kinds of material which form the great mass of the hills is also seen, and the general fact 

 seems clear that these materials came from the northeastern country, which formed then as now 

 the higher portion of the mountains. And, though the order of succession of the different kinds 

 of material is sometimes different at different localities, and there is no end of variety in the de- 

 tails, yet in all the facts last stated, that is, in almost all the leading, general features of the sub- 

 ject, these hills of Placerville present an epitome of the whole gravel region so far as I studied it 

 in 1871. 



There is a range of country running from near the South Fork of the American at the mouth of 

 Webber Creek, and passing just west of Shingle Springs in a direction a little to the east of south, and 

 passing just east of Latrobe to the edge of the canon of the Cosumnes just below the mouth of Big 

 Canon Creek, which is so high that I do not believe it has ever been crossed by any of the large 



And I think there is far more probability that the 

 South Fork of the American may once have crossed the ridge at Centreville and joined the North 

 Fork higher up than now, than that it ever found its way to the valley as a separate stream. In- 

 deed, it seems but natural that, when the locality of the junction of two mountain streams is 

 shifted, it should be changed to points lower down the mountain slope rather than to those which 

 are higher up. Such seems to have been the case at Forest Hill, and such may very possibly have 

 been the case here. 



The immense quantities of gravel and other river debris accumulated in the vicinity of Folsom 

 speak volumes in favor of the idea that the debouchement of the American Eiver from the moun- 

 tains has never since the earliest gravel period been far from where it is to-day ; while the absence 

 of any corresponding quantity of similar materials between these and the vicinity of Michigan Bar 

 is equally strong evidence that since that time no very large stream has reached the valley at any 

 point between the debouchement of the Cosumnes and that of the American. 



I can probably add little of any moment to what is given in the detailed notes respecting the 

 region I traversed in going from Placerville, via Fairplay, Grizzly Flat, Brownsville, Indian Dig- 

 gings, Volcano, Fiddletown, Mud Springs, and Latrobe, to Michigan Bar. It will be seen that in 

 the country passed over on this trip, from Fairplay through the localities named to Fiddletown, 

 there are great quantities of volcanic matter, and in places considerable gravel beneath it in the 

 ridges. But I have been able to trace no definite channels here. I saw nothing, however, to 



streams coming from the mountains above. 



s 



o 



conflict with the theory that the general course of the streams was southwesterly here as well 





