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The Quicksilver Mines of Oregon. 05 



THE QUICKSILVER MINES OF OREGON. 



The quicksilver mines that have been worked in Oregon, are 

 situated in the northeastern part of Douglass county, on the head 

 waters of the Umpqua river. 



There are three that have been worked, the Nonpareil, Bonanza, 

 and Elk Head. The former 'is situated on Calapooia creek, eight 

 miles northeast of Oakland. The main lead, or deposit, is at the 

 juncture of the sandstone on the west and basalt on the east, 

 which is of a hard quality, and in some places partakes of the col- 

 umnar structure so common in other parts of the state. There are, 

 however, a few places where sedimentary rocks are on both sides of 

 the lead, yet they seem to be only in spots, forming, perhaps, only 

 cap rocks of no great depth. The veins of ore are much distorted, 

 running a little east of north and west of south, of uneven widths, 

 composed of volcanic tufous rock intersected by veins or ribs of jas- 

 pery iron ore formed by infiltration through crevices of water con- 

 taining iron protoxide and silicic acid. The dip of the ledge is from 

 west to east, though it is difficult to follow on account of its sinuosity 

 and its swelling and pinching. 



The walls are both volcanic rock. The sandstone on the west 

 not reaching quite to the vein proper, neither does the hard basalt, 

 as a rule, reach the vein on the east, there being a softer tufous rock, 

 of varying character and hardness, composing the walis, gradually 

 emerging into the other rock as they recede farther from the vein 

 which is from a few inches to many feet in thickness. The cinna- 

 bar being in spots, specks and streaks throughout the entire vein 

 which is richer in some places than others. 



A small body of limestone has been found within a few yards 

 of the vein in the sandstone. There is in a few places what appears 

 to be a cap rock of sandstone and conglomerate overlying the basalt 

 to the eastward near this mine, as also the Bonanza. This, however 

 is not without doubt as to its extent in depth. The trap appears to 

 have pushed the sedimentary rocks out of their original position. 



The Bonanza mines are situated some three miles southwest of 

 the Nonpareil. The walls of the Bonanza are the footwalls of the 

 sandstone on the west, but on the east it is usually slate. However 

 this slate is most likely only a cap on the basalt, which evidently 

 underlies the slate at no great depth. The mountain being several 

 hundred feet high, it has been worked mostly by tunnels instead of 

 shafts. There are many small veins of very rich ore running in 

 various directions through the main vein or lode, which is in places 

 two or three hundred feet wide. Many fine specimens of the sul- 

 phides of mercury have been taken from this mine. It contains the 

 mettacinnabarite, found only in this mine and, the St. John's mine in 

 California, which ore is more of a mechanical mixture than a chem- 

 ical compound; but is, however, more or less mixed with the red 

 sulphuret, as its streak is often quite red. 



