132 



THE AURIFEROUS 6EAVEL8 OF THE SIERRA NEVADA. 



and the channel opened, so that a very good idea can be had of its struc- 



ture. 



This lava flow has long been known and has excited much attention, not 

 only on account of its peculiar features, but because of its richness in gold. 

 It has already been referred to as having been described by Dr. Trask (page 

 68) in his Keport for 1856. Mining was commenced under this flow in No- 

 vember 1854, the first discovery having been made, it is said, near Shaw's 

 Flat, by the Brown boys, who in cleaning up an old shaft struck gravel, which 

 although only one foot in thickness was very rich in gold. Two years later, 

 judging from Dr. Trask's description, there must have been a good deal of 

 activity displayed here. The region was examined by the writer in 1861, 

 when work was going on at several places ; when revisited, ten years later, 

 there seemed to be nothing more doing. All the tunnels, between Shaw?® 

 Flat and Jamestown at least, had been abandoned. Mr. Remond also in the 

 course of his examinations near Sonora, in 1866, made two sections across 

 Table Mountain. A description of the principal features of this lava flow will 

 be found in Geology, Vol. I., with some sections illustrating its structure and 



peculiarities. 



The fact that the Sonora Table Mountain formerly extended over what is 

 now the canon of the Stanislaus was early recognized by the miners, and is 

 so evident that it could not escape their attention. To one standing on the 

 summit of the mountain at the point of crossing, where it first passes from 

 the west to the east side of the river, and looking from either side over to 

 the other, the evidence of a former junction of the dissevered portions seems 

 to be very clear. There is no mistaking the fact that the portion on the 

 west once connected with that on the east. After crossing here, the flow 

 continued on for about two miles in an easterly direction to a point near 

 where the present town of Springfield is situated, then turned and ran a little 

 east of south in a line nearly parallel with the present Stanislaus, for about 

 ten miles, to a point a little west of Montezuma ; here it divided into two 

 portions, of which one ran west for four or five miles and again crossed what 

 is now the canon of the river and continued down on that side, while the 

 remainder seems to have kept to the east of the present river. From Mon- 

 tezuma downwards, however, the current spread out over such a wide area, 

 and has been so much eroded away, that the original form of the flow could 

 not be restored without much more labor than we have been able to bestow 

 upon it. From the diagram which is here given (Plate D), however, a good 









