STANNIFEROUS DEPOSITS OP TASMANIA. <S9 



the wash-dirt on this claim, or from between loose fallen masses 

 of porphyry, weighed as much as 6 cwt. Not a few of these 

 masses were almost entirely free from the matrix. It seems some- 

 what remarkable that where there are such strong evidences of 

 the existence of lodes in the immediate neighbourhood of these tin 

 ore deposits only one actually well-defined lode has been laid bare. 

 This occurs on the Waratah Company's claim, which is bounded 

 by Messrs. Walker and Beecraft's section on the west, and Messrs. 

 Giblin and Wintle's section on the north. When it is remembered, 

 however, that, although nearly two years have elapsed since mining 

 operations were commenced, and that during that time not half 

 an acre of washdirt has been collectively removed, this apparent 

 anomaly is somewhat modified. Evidences of shattered walls of 

 tin lodes are daily brought to light. It would seem that in the 

 case of Messrs. Walker and Beecraft's rich claim the removal of 

 drifts cannot be carried on many yards further in the direction 

 of the summit of the ridge of the mountain before the source of 

 the rich washdirt is reached. In a hole sunk to a depth of 20 feet, 

 and about 30 yards in advance of the face of the excavation, large 

 masses of tin ore lie so thickly embedded in a cement-like matrix 

 that recourse has been had to the mall and wedge to remove them. 



The eminent geologist and mineralogist of Victoria, Mr. Ulrich, 

 joins issue with me respecting the existence of actual lodes of tin 

 ore at Mount Bischoff. I had the good fortune to be at the mines 

 when he visited them. His opinion then, which he has since 

 published, was that the tin ore occurred in the porphyry as 

 "bunches." Since then the lode on the Waratah Company's claim 

 has been discovered, and most of the other evidences of their exist- 

 ence in other parts brought to light. In the associated sediment- 

 ary strata, numerous crevices and joints are found filled with 

 casserterite, but these are generally too small to have any value. 

 The depth of the stanniferous drift varies from one foot to thirty 

 feet, the greatest depth being as a rule on the steepest slopes. 



Although the euritic porphyry is the chief source of the ore, 

 there are rich deposits consisting of tin and peroxide of iron, as 

 is the case on the Mount Bischoff Company's ground, where a 

 face has been opened up to a depth of thirty feet. This excavation 

 is not more than eighty or ninety yards from the works on Messrs. 

 Walker and Beecraft's claim, and presents entirely different 

 characteristic features. No large masses of white porphyry are 

 seen here, among which the tin ore is disseminated in coarse 

 particles and large nuggets, but, on the contrary, fine-grained black 

 tin is found dispersed through a drift composed of concretionary 

 fragments of iron ore and coarse sand. Ascending the slope of 

 the basin from the face of their works in going to the top of the 

 mount, the tin, iron, and sand assume a cemented condition, ana 

 finally, at the summit, appear in cliff-like masses of a conglomerate 



