120 Procecdhigs of tlic Royal Society of Victoria. 



The Linda Valloy has attracted niucli attention owing to the 

 gokl found in its alluvial, and to the other valuable minerals 

 occurring in the ridge bounding it on the west. As might have 

 l)een expected, in the case of a valley lying between two high 

 mountains composed mainly of the older formations in a highly 

 disturbed region, the geological problems to which it gives rise 

 are very complex. 



The lowest rocks exposed consist of schists (principally 

 hydromica), sandstones, quartzites, and conglomerates. These 

 are all inclined at high angles, and have been assigned to Lower 

 Silurian age. Capping and apparently forming the greater mass 

 of Mounts Owen and Lyell is a great series of sandstones and 

 conglomerates. The Linda Valley is to a great extent filled by 

 more recent deposits. The so-called Silurian rocks occur at the 

 upper end of the valley, and may be recognised again at the lower 

 end on the Linda Creek. The ridge joining Mounts Owen and 

 Lyell at the west extremity of the valley is almost, if not en- 

 tirely, composed of schist. Owing to accumulations of debris and 

 the -occurrence of thick scrub, and consequent difficulty of ob- 

 servation, it is very hard to determine with anything like 

 precision the geological relationships of the rocks in this country. 

 While certain Lower Silurian fossils ha%'e been obtained from 

 rocks in the vicinity, yet, until a careful survey is made, it will 

 be very difficult indeed to assign any given outcrop to a certain 

 age. There are at least two sets of the older rocks with an 

 unconformity between, and it seems quite possible that there ma\- 

 be a third. Thus we should not be surprised if the schists forming 

 the ridge at the head of the Linda Valh^y turned out to b(; 

 Cambrian or even Archaean. 



Pyrites occurs abundantly through these ancient rocks, and 

 micaceous and specular iron is plentiful ; veins of the latter can 

 be seen traversing piidc conglomerate, in which the included 

 pebbles are apparently all of quartz and quartzite. 



One of the piincipal features of the western end of the Linda 

 Valley is the now celebrated " Iron-Blow," a mass of haimatite, 

 and the closely-associated lode (so-called) of pyrites, which is now 

 l)eing worked by the Mount Lyell Company. This mass is 

 apparently interbedded with the country rock, and is inclined at 

 about G3°. The hanging wall is schist, and the footwall con- 

 glomerate. 



