38 On the Geological Distribution of Gold. 



of drift, resting on the bed-rock (clay and chlorite schists) is 

 auriferous, and at the lower part of the drift large rounded 

 quartz-boulders are found resting on the perfectly decomposed 

 schist. In California similar " gravel-hills " are observed, 

 but there they present ridges of more extent and even more 

 elevated, and above the auriferous stratum in some instances 

 a calcareous infiltration has bound together the fragmentary 

 accumulations; while in others a ferruginous solution has 

 produced this effect. In the most of these hills a com- 

 pact ferruginous conglomerate has formed for many feet in 

 depth, and close to the layer of drift. This conglomerate 

 often proves richer in gold than the drift itself. 



It would now appear that the great work of the Creation, 

 as it now exists, was approaching completion ; still, previous 

 to the re-appearance of a new flora, and the re-organization 

 of animated beings, certain additional changes were required, 

 for which the aid of water was yet necessary — some 

 fluvial matters remaining to be distributed. Among the 

 detritus of this period we find that gold makes its appear- 

 ance, particularly in the superior strata of the beds of 

 running waters and among the superficial decomposed 

 mineral compounds which we know as vegetable earth. 

 Among the results of this latter fluvial epoch may also be 

 observed large accuroufations of a finely pulverised sand, 

 spread over plains which we distinguish by the name of 

 deserts, and on which the wind has the power to form sand- 

 hills of considerable extent. 



Viewing the gold as it is found in those countries where 

 moving waters abound — as in South America, where the writer 

 has exercised careful personal observation, the precious metal 

 is seen in small, lamellar, thin particles, all of well-rounded 

 exterior, perfectly clean and smooth surface, generally not 

 much larger than a linseed, the quality being — the lowest, 

 79-02 gold, 20-98 silver; and the highest 91-44 gold, 08-56 

 silver. 



Mineral and Metallic Compounds associated with Gold of the 

 last fluvial. — Titanic iron oxide, chromiferous oxidulated iron, 

 oxidulated iron sand, prot-oxide and per-oxide of iron, rutile, 

 titaniferous iron with manganese, nigrine, rarely oxide of 

 chromium, oxidulated copper (Siberia), chloride of copper 

 (S. A., Atacama). Most of these compounds appear in the 

 form of a fine sand. 



Among general remarks we may here state, that with the 

 auriferous depositions of this period are found some precious 



