ORIGIN AND MODE OF OCCURRENCE OF GOLD-BEARING VEINS. 127 



But veins of auriferous quartz have also been found to exist in 

 the granite and other igneous rocks of that Colony, and it has 

 been shown that it is only where the sedimentary rocks have been 

 intersected and disrupted by igneous ones that the veins of 

 auriferous quartz exist to any extent in the former, proving 

 beyond a doubt that the near vicinity of igneous rocks is 

 conducive to the formation of quartz veins containing gold and 

 other minerals. A description of some of the quartz veins of 

 Victoria and of the other colonies of Australasia will give an 

 idea of their different modes of occurrence, and supply reliable 

 data to be considered in conjecturing as to the possible manner 

 in which they were formed. 



The quartz veins of Victoria may be divided into two great 

 classes, viz. : — - 



1st. True Lodes, or those that have well-defined walls and 

 continue on a certain strike and dip for a considerable distance, 

 excepting in places where they are heaved by subsequent faults 

 or slides, in which cases they are abruptly broken off, but may 

 be picked up again in the direction in which the slide or fault 

 has heaved or thrown them. 



2nd. Segregation Veins, or those bearing evidence of being 

 accumulations of quartz in irregular fissures, cracks, or cavities, 

 or upon some natural planes — such as cleavage, bedding, or 

 jointing in the rock. The latter veins comprise a very large 

 portion of the auriferous quartz veins of the colony ; and it is a 

 matter of opinion as to whether many seemingly true lodes are 

 not of the same character, differing only in their more regular 

 form. 



Sometimes veins included under Class 1 (True Lodes) may 

 bear evidence of being formed on a line of fault, and may be 

 considered as true fissure lodes, while in other cases they coincide 

 with natural planes of the country rock, such as those of bedding, 

 or cleavage, etc., and an open question arises as to whether they 

 should be considered as true lodes or segregations of ore that have 

 accumulated on a natural plane in lode form. However, all the 

 varieties of quartz veins in Victoria may be comprised under one 

 or other of these two classes ; the second class (Segregation 

 Veins) embracing a great variety of deposits occurring under 

 different conditions, as will be seen from the following description 

 of some of the veins of the colony : — 



Victorian Gold Mines. 



The rocks that contain the gold veins and deposits of Victoria 

 are sedimentary rocks, chiefly, if not wholly of upper and lower 

 Silurian age. These are more or less altered, and while some 

 contain fossils, others consist of chloritic micacous and granitoid 



