382 



SUPPLEMENTARY INVESTIGATIONS IN THE GRAVEL REGION. 





about 170 feet in all. 



side of the claim, carries very large boulders. It is reasonable to suppose that the deepest part of 

 the channel will be found farther to the south than the present limits of the workings. 



The diagram (Plate N, Fig. 2) represents a portion of the face of the Enterprise bank. The 

 upper fifteen feet and the forty feet below the intervening stratum are made up of a rolled vol- 

 canic gravel. The intervening stratum is a compact volcanic tufaceous rock ; below this volcanic 

 material comes the light-colored, fine, quartzose gravel. 



A capping of volcanic material is found on Mooney Flat Hill, and on the hill called " Clark's " 

 in my former report. This latter name I find is not in use at Smartsville, and in its place I should 

 substitute " Smartsville." The thickness of this capping on Mooney Flat Hill may be taken as 



On Smartsville Hill the thickness is less. This volcanic matter is mostly 

 in the form of a rolled gravel, or a rounded gravel, the spherical form of which may be due in part 

 to a concentric structure. I have brought a few specimens from this place, which fairly represent 

 the form and character of the pebbles, but not the size.* The gravel of volcanic origin is inter- 

 stratified to some extent with layers of solid and compact tufa or lava. The best exposures of this 

 volcanic material are on the south side of the Mooney Flat Hill at the Enterprise bank, in the 

 tunnel through the hill from the Enterprise to the Mooney Flat mines, and along the boundary 

 ditch which separates the ground of the Excelsior from that of the Nevada Reservoir Company. 

 This last-mentioned ditch is a shallow excavation extending from a point near the present Enter- 

 prise bank to the top of the hill. I went over this ground very carefully, and became satisfied 

 that, above the level of the tunnel, which starts in the lower volcanic stratum shown in the section 

 (See diagram, Plate N, Fig. 2) there is very little, if any, material, rolled or compact, which is not 

 of volcanic origin. The tunnel is 972 feet long, and six feet by six in cross-section. Its course is 

 jST. 65° E. (magnetic). The lowest compact lava stratum is from five to ten feet thick, and crosses 

 the face of the Enterprise bank about fifteen feet below the present top. Immediately below 

 this compact stratum there comes a layer of rolled volcanic pebbles, thirty to forty feet in thick- 

 ness, and of a pale bluish-gray color. The stratum above the compact lava is similar in character. 

 The face of the bank was, of course, inaccessible, but I could determine the character of the layers 

 by tracing them to the right and left of the bank. 



Below Mooney Flat Hill and Smartsville Hill there is no lava capping in place over the gravel, 

 but there have been found from time to time, near the surface and along the rim-rock, " float " 

 boulders of lava with gold-bearing gravel adhering to them. In all probability the volcanic 

 gravel, by itself, is not auriferous. I do not know that it has ever been tested at this point. 



It is well known that there have been several bed-rock tunnels driven from time to time to open 

 up different portions of the Smartsville ground. Those now owned by the Excelsior Company 

 are as follows. The list was given me by Captain Flint, and includes portions of the flumes as 

 well as the tunnels. 



1. 



2. 



Name. 



Big Ravine Flume 



Babb and Michigan Tunnel 



Length. 



4,800 feet 

 2,000 " 



Width. 



4 feet 

 6 " 



3. 



" " " Flume 

 Pactolus Tunnel 



2,800 

 1,600 



U 



U 



4 

 6 



a 



a 



4. 



" Flume 

 Cement Claim Tunnel 



3,400 

 1,800 



u 

 u 



6 



u 



a 



5. 



" " Flume 

 Blue Gravel Tunnel 



3,100 



1,808 



u 



u 



4 

 6 





6. 



" " Flume 



Enterprise Tunnel 

 " Flume 



3,410 



3,092 

 6,156 



u 



■ 



u 



f? 



? 

 4 



a 



a 



u 



7. 



Mooney Flat Tunnel 

 " " Flume 



3,300 



3,480 



u 



8 

 5 



a 

 it 



Height. 



8 feet 



Depth. 



34 inches 



Grade. 



6 inches 



36 



U 



5 to 8 " 



8 " 



36 



u 



7 " 



8 



U 



8 " 



34 



U 



4 to 7 



it 



32 



a 



? 





32 



it 







1 « 



34 



ii 



6 " 



8 " 



34 



a 



5 " 



* These pebbles, as well as the tufa mentioned further on, prove on examination to be andesitic. 





