217 



Owen, drained on the eastern side by the River Linda, and on 

 the western side by the Queen Eiver (both tributaries of the 

 King Eiver). The " Iron Blow," worked by the Mount Lyell 

 Gold-mining Co., appears to be quite unique in the history 

 of gold mining. Hitherto, in Tasmania at least, reef gold 

 has been worked in quartz veins or dykes, traversing the 

 Lower Silurian slates, quartzites, or conglomerates. 



The " Iron Blow " has little resemblance to the ordinary 

 auriferous veins. The absence of quartz throughout the 

 more characteristic parts of the auriferous formation is 

 especially remarkable. Where it does occur within the defined 

 walls of the " blow " it is inconspicuous. 



From various accounts it would seem that the formation 

 occupies an enormous chasm penetrating or traversing the 

 hydro-mica schists, the walls of which are stated by Mr. 

 Thureau to be fully 280 feet apart. The outcrop of the 

 " Iron Blow " has been traced for about If miles along its 

 strike. The deposit itself is variously termed " lode," " iron 

 blow," " blue iron," and " auriferous iron schists." 



The strike of the principal fissure is nearly parallel with 

 the direction of the southern face of Mount Lyell and North 

 Mount Lyell, i.e., in a direction nearly North 28° W. 



Mr. Thureau also states that both hanging and foot walls, 

 so far as they have been observed, dip at an exceedingly high 

 angle in the same direction ; the former at an angle of about 

 75 degrees. W., the latter about 64 degrees West. Where the 

 mass of auriferous stuff is worked, a cross section has dis- 

 closed that about 57 feet, or about a fifth of the width, is 

 composed of the more richly auriferous matrix, consisting 

 mainly of peroxide of iron and barytes, either of a soft 

 laminated character, or pulverised into a powdery mass of a 

 dark purplish color. The remaining four-fifths, or western 

 portion of the section, is in the form of solid pyrites ; but an 

 analysis made for me by Mr. Fred. Ward, the Government 

 Analyst, proves that it is essentially the same in character as 

 the softer mass to the east, and the latter is no doubt simply 

 a decomposed form of the more solid pyrite mass of the 

 •western side. Strings and veins of solid barytes also are found 

 penetrating the mass ; and gold is found, in more or less ex- 

 traordinary richness throughout the whole ferruginous mass. 



When it is affirmed, as stated by Mr. Thureau, that the 

 dark purple-colored rock has yielded at the rate of 187oz. 

 per ton, its phenomenal richness is at once appreciated ; and 

 although it is too much to expect that this average will be 

 maintained generally, it is enough to indicate that the deposit 

 is probablv the richest hitherto known. 



The following analyses, kindly prepared by Mr. Ward, are 

 of much value, as they will afford to those who are interested 



