534 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 10, 



of the movements which have placed the Silurian rocks in their 

 present highly-inclined and contorted positions, and given them their 

 very uniform meridional direction. There is very little true slaty 

 cleavage until we get low in the Llandeilo beds. 



The gold-bearing drifts that rest on these strata are of, at least, 

 three distinct ages. The oldest drifts (No. 1, figs. 1, 2, 3) are, I 

 believe, for the most part, freshwater Miocene deposits. The only 

 fossils hitherto found in them are, however, vegetable — consisting 

 of large quantities of wood, trunks of trees, seed-vessels, &c, at 

 various depths to 780 feet. 



The deposits themselves consist of fine clays — black, yellow, white, 

 red, and mottled, siliceous sands and quartz-gravel, with large water- 

 worn pebbles. These are often overlaid by sheets of lava, in the 

 manner shown in the Bendigo and Ballarat sections (figs. 2 and 3, 2). 

 The rock consists of basaltic lava, &c, sometimes porous, sometimes 

 solid and concretionary ("bluestone"), with interposed red, white, 

 and yellow sometimes sandy clay (intersected in the lava in fig. 3) . 

 Whether this is a volcanic or ordinary sedimentary deposit, is at 

 present uncertain. 



Near the coast there are distinct and undoubted Miocene beds, 

 full of marine shells, occupying (apparently) the same geological posi- 

 tion relative to the tertiary sheets of basaltic lava that the gold- 

 bearing drifts do, which I consider to be freshwater Miocene deposits. 

 By far the greater portion of these immense sheets of lava were 

 spread out towards and during the close of the Miocene period ; and 

 their irruption has evidently had nothing whatever to do with the 

 formation of the gold. The trap-plains to the westward are very 

 extensive ; and there is every probability of gold-deposits existing 

 underneath the trap over the greater portion of them. The limit, 

 therefore, to the period during which these Tertiary gold-deposits of 

 Victoria may be profitably worked may be regarded as indefinitely 

 remote. I wrote to Jukes four years ago about the passage of these 

 Miocene gold-drifts under the lava-plains*. 



The gold- beds above referred to as being probably of Miocene 

 age extend to elevations of about 2000 feet above the present sea- 

 level ; and their greatest thickness, including contemporaneous trap- 

 pean beds, is about 300 feet ; at least, there are no places where 

 they have yet been proved to exceed that thickness. 



Resting on the lava-sheets is a Pliocene drift (No. 3, figs. 1, 2, 3), 

 containing gold and bones of extinct and living marsupial qua- 

 drupeds. It consists of clays, sands, and angular and waterworn 

 gravel, formed during the denudation of the Miocene drifts and trap, 

 and the granites and Silurian strata. It often rests on the Miocene 

 beds without the intervention of basalt ; and thus two gold-bearing 

 "bottoms" occur. I have only seen one instance of this Pliocene 

 drift, or rather marine beds of the same age, being overlaid by vol- 

 canic matter, — viz. at "Tower Hill," near Warnambool, where raised 



* Mr. H. Rosales also adverts to the gold-drifts that are older than the basalt, 

 in his paper in the Quart. Journ. Geol. Soc. vol. xi. p. 397. — Edit. 



