128 ORIGIN AND MODE OF OCCURRENCE OF GOLD-BEARING VEINS. 



schist and other metamorphic rocks, and intrusive and disruptive 

 igneous rocks also occur in great variety. A common mode of 

 occurrence under which the auriferous quartz veins of Victoria 

 are found is that of true lodes, either coinciding with the bedding 

 or other natural planes of the country rock, both in strike and 

 dip, or intersecting the rocks perfectly independent of either, or, 

 as in some cases, coinciding with the one and not with the other. 



I will now proceed to give some characteristic examples of 

 these different modes of occurrence under which true lodes, or 

 those that have well defined walls and a certain general dip and 

 bearing, are found to exist in the colony of Victoria. In doing 

 so I will borrow largely from that excellent work on the peculiar 

 characteristics of the Victorian quartz veins, viz., Brough Smyth's 

 " Gold-fields and Mineral Districts of Victoria," but at the same 

 time, as often as possible, make use of my own observations as 

 regards some of the lodes of which I have an intimate knowledge, 

 giving as many examples of quartz veins that have been examined 

 by myself as this essay will allow of, without subjecting myself 

 to be considered tedious. 



Of true lodes that coincide both in strike and dip with natural 

 planes in the containing country rock, the following from 

 Brough Smyth's work already referred to, is a good example, 

 showing as it does the lode in cross-section at different levels. 

 ( Vide Sketches of Main Lode of the Catherine Reef at Clunes, 

 Victoria) : — 



Fig. 1. — Cross-section, between No. 2 and No. 3 levels. 



Fig. 2.- — -Cross-section, 25 feet below last. 



Fig. 3. — Cross-section, 25 feet below last. 



As may be seen from these sections the lode varies in thickness, 

 having, however, an average of about five feet, and the foot wall 

 is very irregular, and has many spurs of quartz running into it. 

 Upon the hanging wall-side of the lode is a vein of laminated 

 quartz, varying from one to six inches in thickness, and upon this 

 vein is a layer of sandstone, two feet thick which is overlain in 

 turn by a ' flu can' about fifteen inches in thickness, and again by 

 sandstone, which is supposed to be the real wall of the lode. The 

 foot-wall is said to be slate, distinctly laminated parallel to the 

 lode and its irregularities. 



Of those lodes or quartz veins which do not seem to have been 

 formed upon any natural planes of their containing rock, but 

 which cut through the rock independent of such planes, there are 

 many examples to be found among some of the richest quartz 

 veins in the colony. Those shewn in section Fig. 5 and Fig. 6 

 are very good examples of this mode of occurrence, and in the 

 course of this essay I shall speak of many others of a similar 

 character that I have personally examined. 



