Vol. 60.] OF THE GOLD-DEPOSITS OF BAEKERVILLE. 391 



very dilute solutions, their volume is large and time is unlimited, — 

 in the course of ages produces a zone of great enrichment in the 

 neighbourhood of the permanent water-level. 



The writer has seen specimens of gold showing the impress of the 

 pyrites upon which the gold had been precipitated, clearly proving 

 the order of deposition to have been, first, the pyrites in the reef, 

 and, secondly, the gold on the pyritic nodule. 



While the enriched zone was being formed, the weathering of the 

 surface continually removed the leached outcrop and constantly 

 exposed fresh surfaces to the atmospheric influences : these, having 

 become more active than the solution and precipitation, in time 

 overtook the latter agencies and wore down the enclosing rocks 

 until what had been the permanent water-level became a very rich 

 outcrop. 



To the weathering of such outcrops we may assign the rich 

 placers. 



"While the comparatively-recent removal has not left time for 

 another bonanza to be formed, it is only a matter of time when 

 the present exposed outcrops will become honeycombed gossans, 

 indicating rich zones below. 



With the exception of the Perkins ledge on Burns Mountain, no 

 free-milling ore has been encountered which in any way adequately 

 accounts for the splendid placers of Williams', Lowhee, Lightning, 

 Grouse, and many smaller creeks. 



The gold found in all these placers is of purely-local origin, and, 

 being to a great extent associated with quartz, must have come from 

 reefs not far away. Indeed, some of the nuggets show no signs of 

 attrition, and would seem to have been derived from ledges in their 

 immediate vicinity. As no such ledge has been discovered in the 

 creek-bottoms, and any washing, such as a theory of transportation 

 from up stream requires, would have broken up the delicate 

 filaments of gold, some other explanation must be looked for to 

 account for these unwashed grains. 



The most probable and satisfactory one is that these nuggets were 

 brought to their present place in a soluble matrix, and in the course 

 of time the matrix dissolving away left the gold in the condition in 

 which we now find it. This matrix was most probably calcite, as 

 nuggets have been found with limestone attached to them, and 

 many large beds of limestone traverse the schist-belt. 



The origin of the quartz-bearing nuggets is easily accounted for 

 when we consider the conditions of the country in middle and later 

 Tertiary times. By the former date the hills now existing had been 

 swept clear of the pre-Tertiary gravels, and the deep channels 

 eroded to their present depth. After the hills had been exposed to 

 the action of frost and weather for many ages, the soft schists 

 were decomposed and gradually washed into the present creek- 

 bottoms, together with the gold set free from the rich surfaces of 

 the quartz-veins that we now see on the mountain-tops ; and with 

 the gold from many others hidden under the Glacial and post- 

 Glacial gravels. 



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