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THE CHANNEL: NEAR NEVADA CITY. 
miles, and it is not easy to believe that the deposit at Peck’s is in the direct continuance of the 
Manzanita gravel; but it is even more difficult to suppose that the stream went in the opposite 
direction. There are also difficulties in the way of supposing that a tributary to the main Man- 
zanita channel passed through here, in a direction from north to south, which do not exist at 
Dean’s Tunnel, where J made a supposition of that kind. Another explanation, which seems in 
many respects the most plausible of all, is that the gravel under Cement Hill at Dean’s and at 
Peck’s has no connection at all with the Manzanita channel; at least no direct connection. It 
may have been that the Manzanita channel choked up and overflowed into some depression at the 
north and then flowed in its new channel down towards Peck’s Diggings; but I am at present 
more inclined to the opinion that there was a small, nearly parallel, channel, perhaps only a large 
ravine, which came from somewhere near Round Mountain, and passing along where now we have 
the north side of Cement Hill, emptied into the Yuba. The tracing of hidden channels is always 
a matter of great difficulty, because we can scarcely ever be sure that the particular piece of bed- 
rock which we see exposed is not exceptionally high or exceptionally low, and so I advance the 
above solution of the problem, not as a final settler of the disputed question, but as a possible and 
plausible explanation. I said, above, that there were difficulties in the way of supposing that 
Peck’s Diggings were on a tributary which helped feed the main Manzanita channel. One of the 
chief of these is that the present ravines and creeks, across which any such tributary must have 
gone, do not show, and have not shown, any such amount of gold as would have been probable, if 
the tributary had ever existed. Concerning the country to the south of Cement Hill, and along 
Rush Creek, I shall have more to say when I review the notes of my second visit to Nevada, made 
toward the end of September. At Peck’s Diggings I saw some of the largest granite boulders that 
I found anywhere in the gravel region ; the bed-rock was also granite. The pay gravel was mostly 
or entirely quartz sand and boulders, and not very thick, say from one to four feet. A consider- 
able part of the gravel on the bed-rock to the east has been worked out by means of a tunnel 
and drifting. The mouth of this tunnel is on the Long Tom Ravine side of the spur, between an 
eighth and a quarter of a mile about south-southeast from Peck’s house. The tunnel itself was said 
to be 600 feet long, running about west-southwest. I took an observation for altitude at its mouth, 
and, allowing six feet for the rise in the tunnel, made the bed-rock under the hill twelve feet higher 
than the exposed rock in Peck’s Diggings. Mr. Peck supposed the difference would be fourteen 
feet, which was an excellent corroboration of my measurement. Later in the season, October 1, 
I visited the place again and repeated my observation at the mouth of the tunnel, obtaining a result 
agreeing very closely with the first one. This higher bed-rock on the east would seem to indicate, 
if anything, that the course of the old channel was directly towards the present bed of the South 
Yuba. When the washing away of the whole bank has been accomplished, —as is contemplated 
by Messrs. Rolfe and Stranahan, who had arrangements nearly completed for commencing work as 
soon as a supply of water could be had, —and more bed-rock is exposed, we shall be in a condi- 
tion to judge with considerable certainty as to the old channel’s course. A peculiar feature of the 
end rim at this point is that it does not rise above the general level of the bed-rock (the only 
place in the county, according to Mr. I. N. Rolfe, of Nevada City, where this is the case). Why 
the rim should so universally bend upwards on all sides of the gravel deposits in the Sierra is a 
question into the detailed discussion of which I will not now go. Possibly in this ease the fact 
that the bed-rock is granite may have something to do with the solution, especially if, as I have 
supposed, the old channel went down nearly where Native American Ravine now is to the South 
Yuba. Iam not prepared to say whether or not there are any other gravel deposits on a granite 
bed-rock where the position of the rim has been noticed. In the great majority of cases the bed- 
rock is slate, which may possibly have swollen and expanded (as some think) when exposed to the 
action of the air, though I have no fact nor experiments to adduce in corroboration. 
The following is a résumé of the observations made in the vicinity of Ne- 
vada City, at various times during the season of 1870, by Professor Pettee, 
