166 Journal of the Mitchell Society [^March 



as free gold, and not in chemical combination with the iron sul- 

 phide or as a gold sulphide. Specimens were found in which 

 free gold occurred in perfectly fresh pjrite. The gold runs out 

 into very minute cracks in the pyrite, so that it is impossible to 

 crush the ore fine enough to liberate all this gold without caus- 

 ing slimes. For this reason all the free gold cannot be saved 

 by amalgamation. 



The veins have a lenticular structure, as observed in hori- 

 zontal and vertical planes, varying very widely in width, both 

 along the strike and dip, and are separated by bands of schists or 

 slates from other similar quartz veins. The ore body of this 

 band of mineralized slate can readily be divided into two types: 

 one consisting of numerous very narrow stringers of quartz, 

 lying along the planes of schistosity of the rock, and which are 

 separated from each other by narrow bands of slate which con- 

 tain more or less pyrite, but which are not very silicified ; and 

 the other type containing larger masses of quartz occurring in 

 veins or seams, and the slates inclosing them are silicified to a 

 much greater extent. 



There is great variation in the values carried by these ore 

 deposits, and there seem to be well-defined ore shoots which also 

 have a lenticular structure and which are richer than the balance 

 of the vein. In some instances the foot and hanging walls are 

 well defined, but in many cases the walls of the vein could only 

 be determined by assaying the ore to determine to what extent 

 the vein could be profitably worked. To one who is unfamiliar 

 with this formation it is often very difficult to distinguish be- 

 tween the rich and lean portions of the vein. It is absolutely 

 necessary in working this type of deposit to constantly sample 

 the ore to determine its value, and the position of the vein 

 for ore seams. 



Diabase dikes have been observed cutting the schists and ore 

 deposits, but they have been intruded subsequent to the forma- 

 tion of the ore, and it must have faulted or displaced the ore 

 deposits but very little. 



Three diabase dikes have been observed, two of which were 

 exposed in the underground workings and the third at the ex- 

 treme end of the "mine tract" in an open pit. 



