122 Proceedings of the Royal Society of Victoria. 



of the conglomerate is a hard, silicious sandstone. The intei*- 

 stratified sandstones, wliich oc-cur in beds of considerable thick- 

 ness, vary greatly in character, some being tine, others coarse, 

 and others highly micaceous. A bed of the micaceous sandstone, 

 overlaid by a fine conglomerate, forms the summit of JMount 

 Lyell. From the conglomerate and sandstones lying at the 

 western end of Mount Lyell gold has been olitained in more or 

 less payable quantities. The rocks liave in general an appearance 

 of great antiquity, and extending as they do over a large tract of 

 country, their origin, geological age, and the position of the 

 quartzitic highlands of whicli they are tlie debris are questions of 

 great interest. So far as our examination of these beds went, 

 they were unfossiliferous ; but certain sandstone boulders con- 

 taining fossils found on West Mount Lyell, and also on the 

 button-grass plains lying east of the King River, may yet be 

 traced to them. Mr. Moore is of opinion that they should be 

 classified as Devonian. Mr. Montgomery, Government Geologist, 

 in his recent paper on " Glacial Action in Tasmania," states that 

 the Owen conglomerates are conformably interbedded with the 

 quartzites and schists of this district. If he refers to the con- 

 glomerates forming the mass of Mount Owen, as we presume he 

 does, our observations lead us to believe that this is erroneous, 

 and that, as we have already stated, there are two sets of 

 conglomerates here — one intercalated with the schists and sand- 

 stones, the other — the massive Owen conglomerates — lying 

 unconformably over them. 



Among the beds of later origin in the valley is a soft black 

 clay, called by the miners "pug." It attains a considerable 

 depth in places, and rests unconformably on all the older rocks. 

 It is in places stratified, and is said to contain intercalated beds 

 of lignite. It is reported that shells have been found in it, 

 though w^e were unable to detect any. It contains numerous 

 particles of free pyrites, and would appear, without doubt, to 

 have been formed by the disintegration of the adjacent schistose 

 rocks containing pyrites. Its distribution is confined to the 

 western end of the valley. There is a good outcrop of it just 

 beneath the Iron Blow, and it may be also found at Karlson's 

 Face and at a considerable elevation on the saddle on the Copper 

 Creek. It is probably of lacustrine origin. 



