Intelligence and Miscellaneous Articles. 471 



reached the slate formation which prevails in this part of the gold 

 district. We penetrated on this occasion some forty or forty-five 

 miles beyond the " dry diggings," and after leaving the quartz twelve 

 or fifteen miles up, scarcely a particle of gold was discovered. 



As I have mentioned, the prevailing rock of the gold region near 

 the Rio de los Americanos is slate. There are many varieties of it 

 — some shaly and friable, others hard and massive, somewhat resem- 

 bling greenstone. The laminae of the slate beds are nearly perpen- 

 dicular, and their direction about N.N.W. and S.S.E., or nearly the 

 same as the direction of the range. These slate beds often include 

 dykes or beds of quartz rock several feet in thickness. At the dry 

 diggings above-named, I passed at right angles over the upturned 

 edge of continuous strata of slate a distance of four or five miles ; 

 and in the same direction, slate beds occur several miles further on, 

 but I had not the means of knowing that they were a part of the 

 same great deposit. 



In some of the richest explorations yet made, the slate formation 

 immediately underlies the stratum of drift or diluvium which con- 

 tains the gold, and much of the gold is found in the crevices of the 

 slate, the rough edges of the upturned strata forming innumerable 

 receptacles or "pockets," as they are called, into which the metal has 

 originally found its way, from its own gravity assisted by aqueous 

 agency. It is this accidental association of the gold with the slate 

 rocks which has caused the statement to be frequently made, even 

 by persons of much general intelligence, that the gold exists in 

 the body of the rock itself, and forms a component part of it, in the 

 same sense that iron pyrites forms a part of the rocks in which it 

 occurs. But I have nowhere seen gold among the slate, except in 

 circumstances where its presence could be accounted for by its in- 

 troduction from without, a close scrutiny readily discovering some 

 cleft or opening through which it might have entered. The richest of 

 these " pockets" are in the bottoms of sharp ravines which seem to 

 have been notched into the body of the slate, and generally in situ- 

 ations where the bottom of the ravine, after descending at a consi- 

 derable inclination for some distance, becomes more nearly horizontal. 

 Just below a sudden descent or precipice, in the bottom of a dry ra- 

 vine, gold is often found in the cavities in great abundance, From 

 such a spot Mr. Douglass extracted a pound of gold in a few hours, 

 even after the place had been previously "dug out," as was sup- 

 posed, and abandoned. 



I have noticed in published accounts, many erroneous statements 

 respecting the geological position of the gold. Some have said there 

 is no particular formation in which the gold occurs, but that in dif- 

 ferent places it is found in different kinds of earth or rock. You will 

 not need to be informed that this is without foundation. So far as 

 I have been able to examine, or can learn from competent witnesses, 

 there is but one geological formation with which the gold of the 

 Sierra Nevada is associated and in which it uniformly occurs. This 

 is the stratum of drift or diluvium, composed of a heterogeneous mix- 

 ture of clay, sand, gravel and pebbles, and varying in thickness from 



