1881.] 47 J fCfcance. 



thin quartz veins or disseminated through the mass. As erosion pro- 

 gresses, the decomposed schist is converted into gravel, the lighter and 

 finer particles of clay, mica, etc., being easily washed out by the percola- 

 tion of rain water, leaving the heavier minerals and the larger quartz 

 fragments behind. Thus an essentially concentrating process is and has 

 been constantly progressive since the Glacial period, and the gravel now 

 found lying as a surface covering from one to thirty feet thick may, and 

 probably:' does, represent several times its thickness of rock, the coarser 

 and heavier fragments of which alone remain. 



The thickness of the gravel in the South Mountain region probably 

 averages from six to nine feet, but I consider that this represents the re- 

 mains of at least twenty or thirty feet of rock. On this basis the gravel 

 should contain more than three times as much gold as an equal bulk 

 of the mother rock — it is, in fact, found to be much richer. 



The streams draining this region have carried away millions of cubic 

 yards of this gravel. The old river bed workings in California have 

 shown that all streams act as natural sluices, separating and concentrating 

 the gold and heavier minerals from rocks of less specific gravity, and this 

 action has undoubtedly been operative in these North Carolina streams. 

 The gravel washed into the smaller stream beds dropped its coarser gold 

 before being carried out into the main water courses, and we consequently 

 find that the rich washings were nearly all found in the beds of the small 

 creeks and their tributaries. 



These were thoroughly worked over during the early mining excite- 

 ment, prior to the exodus in '49, yielding to hand panning and to work 

 with the rocker and long-tom, from two to ten dollars a day , They have 

 since been reworked ; at some places the same gravel has been washed 

 three or four times. It was very rich, necessarily so, for working a stream 

 down to bed-rock* is like cleaning up a sluice — it contained the gold 

 dropped from millions of cubic yards of gravel, the accumulation {concen- 

 trates) of thousands of years. 



There are a few localities where these stream gravels are as yet undis- 

 turbed. They will yield good returns, but their area is very small. 



The vast bulk of gravel now remaining to be worked is hill gravel ; its 

 thickness Avill not exceed an average of nine feet, and it is of varj^iug de- 

 grees of richness. 



On some tracts gravel may be found yielding from one to ten colors to 

 the pan, and work done with a rocker may shoAv from five grains to a 

 pennyweight to the cubic yard, a most flattening prospect to the "VTestern 

 hydraulic miner ; but such results are rare. I am inclined to think that 

 five or six grains to the cubic yard is as much as can be expected from an 

 average run of fair gravel. 



The important question, now being solved in a practical way on the 



*The bed-rock was usually not more than two or three feet beneath water 



level. 



