Gold 313 



two to three feet, but the width of the far larger number is 

 very much narrower. Some of the most productive veins aver- 

 age but little over a foot in width. No distinct relation between 

 the country rock and the contents of the veins can be recog- 

 nized. Veins occur in practically all rocks. The character of 

 the filling the quartz varies greatly, and is not constant for 

 the same rock. It even varies in different parts of the same 

 vein in the same rock. The concentration of deposits in and 

 about the granodiorite indicates that the veins are genetically 

 connected with this large intrusion of magma. 



Primary Gold in Quartz Veins; Secondary 

 Gold in Placers 



This in brief is the explanation of the origin of the gold ores 

 of the veins of the Mother Lode. It is a feeble explanation, for 

 it does not explain the real origin of gold, but only how it comes 

 to be there. All the "pay ore" that has ever been discovered 

 has been in veins or derived from veins. Pay ore in a vein, lode, 

 or pocket, derived, as has been stated, from solutions that rose 

 from the depths of the earth, is called primary gold. All 

 quartz-vein gold is primary gold. As the rocks decompose and 

 weathering and erosion break down the rocks, primary gold 

 is released and carried by streams or otherwise down slopes. It 

 then becomes secondary gold. Placer gold gold that is buried 

 in stream gravels is secondary gold. Of all commercially pay- 

 ing deposits of gold none have been in geological formations 

 country rock sedimentary, igneous, or metamorphic. All the 

 gold has come from veins. Veins may and do occur in all 

 kinds of rocks sedimentary, igneous and metamorphic. Veins 

 disregard formations. They cut through rocks of all kinds and 

 all ages. A younger vein, that is, one later formed, may cut 

 across an older vein. Up through the veins have come solutions 

 which contained gold. Here school closes! Where the gold of 

 the solutions comes from we do not know. If somebody im- 



