238 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
posits are mineralized with sulphuret of iron. This substance may form the 
whole mass of the fragment, but is sometimes deposited in crystalline plates 
in the fissures, or as a crust on the exterior. 
The following particulars in regard to the occurrence of fossil wood and 
leaves in the region explored by Mr. Goodyear are extracted from his notes. 
At the Reed Mine, near Deadwood, at the elevation of about 3,600 feet 
the gray cement, as well as the so-called “ chocolate,” — a sort of indurated 
yoleanic mud, — often contains more or less apparently half carbonized wood. 
And, besides these fragments of wood, numerous trees have been found here, 
still in their upright position, with their roots upon and ramifying into the 
bed-rock, and their stems and tops projecting through the “chocolate ” and 
up into the “gray cement.” The trees thus found standing are not very 
large, none of them being much over a foot in diameter. All had their roots 
on and in the bed-rock, and none in the “chocolate.” This last-named ma- 
terial contained also occasional impressions of leaves, very perfectly pre- 
served. At Weske’s Claim, near Michigan Bluff, where fragments of trees 
and wood are common in the cement, some trees are also said to have been 
found in an upright position, with their roots in place on the bed-rock. In 
the Basin Channel, at the Devil’s Basin, Mr. Goodyear saw, at one locality, 
a fossil tree standing vertically in the “ gray cement.” 
Fossil wood is of frequent occurrence in the finer material of volcanic 
origin which overlies the gravel, in the claims along the western side of the 
ridge near Deadwood. At Kentucky Flat, also, there is considerable wood 
in the volcanic ash. In the Oldfield and adjacent claims at Negro Hill, near 
Placerville, the whole mass of the “black lava” contains frequent casts of 
sticks and broken bits of wood, and sometimes, also, delicately preserved im- 
pressions of leaves, which latter are generally more or less bent or twisted. 
The village of Fairplay is just south of Perry’s Creek, a tributary of the 
Middle Fork of the Cosumnes River. There is a large amount of volcanic 
gravel in this region, and at Fairplay considerable mining has been done. 
It is said that in the volcanic gravel on Fairplay Hill there was once found 
a “natural shaft’ three or four feet in diameter, with its sides covered with 
a substance resembling soot. This was probably the cast of an erect fossil 
tree. 
At the Roanoke Mine, near Georgetown, large quantities of wood were 
found in the cement; and it is said that it was a common thing to observe 
here, along the sides of the channel, at about the level of the top of the 
