THE CHANNEL: NEAR NEVADA CITY. 



185 



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 I 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 Maiwanita 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 Eouud 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 

 Push 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 

 A found anywhere in the gravel region ; the bed-rock was also granite. The pay gravel was mostly 

 °r 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 Kavine side of the spur, between an 

 eighth and a quarter of a mile about south-southeast from Peek's house. The tunnel itself was said 

 o 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 

 han the exposed rock in Peck's Diggings. Mr. Peck supposed the difference would be fourteen 

 e e , winch was an excellent corroboration of my measurement. Later in the season, October 1, 

 visited the place again and repeated my observation at the mouth of the tunnel, obtaining a result 

 agreeing very closely with the first one. Tins higher bed-rock on the east would seem to indicate, 

 _ anything, that the course of the old channel was directly towards the present bed of the South 

 U a. When the washing away of the whole bank has been accomplished, — as is contemplated 

 J essrs. Rolfe and Stranahan, who had arrangements nearly completed for commencing work as 

 ^oon as a supply of water could be had,— and more bed-rock is exposed, we shall be in a condi- 

 gn to judge with considerable certainty as to the old channel's course. A peculiar feature of the 

 <■ *™ at this point is that it does not rise above the general level of the bed-rock (the only 

 Pje m the county, according to Mr. I. N. Rolfe, of Nevada City, where this is the ease), Why 

 quesf 111 Sh ° Uld S ° Ulliversall ' y " bcil(l lI l>wards on all sides of the gravel deposits in the Sierra is a 

 that 8 th U ^ nt ° the d0tailed discussion 0^ Which I will not now go. Possibly in this case the fact 

 sul) A r ° Ck i8 8 ranite ma 7 liave something to do with the solution, especially if, as I have 



Yub° ' th ° ° ld channel went down 1K ' ar] y whoro Native American Ravine now is to the South 



bed^* am 1K)t I)repared to sa y wnetlier or not there are any other gravel deposits on a granite 



rock ' 1 Where * he position of the rim has been noticed. In the great majority of cases the bed- 



actio ^ fh WLiCh lmiy P08sibly have swollen and expanded (as some think) when exposed to the 

 10 n of the air, though 1 have no fact nor experiments to adduce in corroboration. 



The following is a resume of the observations made in the vicinity of Ne- 

 vada City, at various times during the season of 1870, by Professor Pettee, 



