ORIGIN AND MODE OF OCCURRENCE OF GOLD-BEARING VEINS. 149 



granular limestone in the same locality. Offenbanya and Nagyag 

 are the names of the principal places where the veins are worked 

 in the district. A slight difference exists between the gangue of 

 the lodes in these two places, but otherwise they are essentially 

 the same. 



In 1873 no less than 416 Mining Companies are said by 

 J. S. Phillips to have been at work in the gold districts of 

 Transylvania, giving employment to 8,369 miners; and in 1877 

 this region produced 27,870 ounces of gold, and 20,108 ounces of 

 silver, besides other metals. 



Many other parts of the world have auriferous veins, but I 

 believe sufficient examples have been given in this essay to 

 embrace all the different and most interesting modes of occurrence 

 at present known. I will, therefore, now proceed to the most 

 probable origin of these various lodes and deposits, and the manner 

 in which they have been formed. 



Before doing this, however, I must devote a few lines to a 

 description of certain special modes of occurrence of gold which 

 appear to bear somewhat closely upon the origin of the reefs. 

 The deposits to which I allude are instances in which rocks have 

 become impregnated with gold. 



There are several remarkable instances of this mode of 

 occurrence of the precious metal, and every year brings to light 

 fresh evidence of certain rocks being charged to a greater or less 

 extent with it. 



It has been known for some years that the granites of the 

 Timbarra Gold Field, New South Wales, contain a certain 

 amount of free gold, more especially where the granite is in a 

 decomposed state, and works have been started to sluice away 

 the soft portions of the rock. It has, however, been proved by 

 assay that in a number of places in the same district the 

 undecomposed granite also carries gold to the extent of several 

 pennyweights to the ton, and I have seen specimens from there 

 in which free gold was visible in the rock (granite), sometimes in 

 good sized specks. I may also mention the Yal Wal Gold Field, 

 likewise in New South Wales, in which district the rock 

 impregnated is a slate. 



The lowest rock of the district is granite, which rises in the 

 spur of the hill west of the Danjera Creek, and may be traced for 

 many miles through the country ; and resting upon this, and 

 standing at angles from 45° to vertical, a series of schists, 

 slates, quartzites, and breccia occur, striking north and south, 

 and dipping east away from the line of elevation. It is only in 

 the softer belts of sedimentary rock that payable gold has yet 

 been obtained, and the characters of the different deposits are 

 very curious. The ore deposits vary from a few inches to 100 feet 



