358 QUICKSILVER DEPOSITS OF THE TACIFIC SLOPE. 



not profess to be perfectly accurate. The Mercury vein was barren below 

 the 400-foot level and has not been traced below the 500. The Manzanita 

 was followed to the 875-foot level, the deepest in the muie. This vein was 

 richest between the 400 and 500 levels and was barren below the 750. 



It is evident that the ore in this mine reached its present position along 

 the fissures from below. There is no reason to suppose that the ore was 

 deposited only near the surface, and vigorous prospecting on the well 

 defined fissures will most likely disclose other ore chambers adjacent to the 

 veins, unless the sandstone should become so dense as to preclude impreg- 

 nations. Had the strata been nearly vertical, instead of almost horizontal, 

 at this locality, it is evident that the fissures would have more or less nearly 

 coincided with the planes of stratification and that, instead of a well marked 

 vein, impregnated strata would have resulted, though everything except the 

 dip of the beds had remained the same. The relation between those two 

 forms of deposit is thus of the closest description. 



Minor deposits. — The Accidental is a vein lying to the south of the Mer- 

 cury, and its projection would intersect the latter at a considerable angle. 

 Cinnabar has been found in it and it is regarded as a hopeful prospect. 

 Other faults have been found containing cinnabar, some of which are par- 

 allel to the Mercury and the Manzanita. 



The Eureka claim is on the same hill as the Napa and in rock of the 

 same kind. The deposit is on an irregular, though well defined fiiult nearly 

 at right angles to the Napa veins. A part of the ore from this mine is in a 

 sandstone breccia, but it is generally quite the same as that from the Napa. 



The Ivanhoe is on the south side of James Creek, also in unaltered 

 sandstone. It has produced only a small quantity of ore. 



GREAT WESTERN. 



■ Geological position.— Thc GrcRt Wcstem has been the largest producer among 

 the mines of the Mayacmas belt. It has yielded over fifty thousand flasks 

 of quicksilver and is by no means exhausted. The underlying sedimentary 

 rocks of the district are for the most part highly metamorphosed. A little 

 unaltered rock exists, but no fossils were found in it. The lithological and 

 physical character of the beds so strongly resembles that of areas, not far 



