324 PROCEEDINGS OF SECTION C. 



present sea level, and at almost exactly the same depth in the 

 Tasmania. When these mines first began to work the water 

 level in them was considerably above that of the sea, and 

 consequently the carbonaceous matter lay a long way below 

 it. 



Now, in Early Tertiary times the configuration of the 

 country differed a good deal from its present aspect. To 

 begin with, the land was probably at least 300 feet higher. 

 This is proved by the fact that \he bottom of the " deep 

 lead " is 270 feet below present sea level, which can only be 

 explained by a subsidence of the land. At the same period 

 the Cabbage-tree Hill was doubtless connected with the Blue 

 Tier Range at its eastern end, and at the western one had 

 not been eaten into to its present extent by the Brandy 

 Creek. The alluvial flat lying to the south was most likely 

 occupied by a lake. As the top of the existing flat is about 

 400 feet above the bottom of the old lead, it is no improbable 

 assumption to make that the waters of the lake stood at a 

 much higher level than the old lead. Consequently, if any 

 fractures and crevices existed in the hill separating them, 

 there would be a possibility of leakage from the lake through 

 the hill. Swamp waters and decaying vegetable matter 

 might thus have got far into the ground. The subsequent 

 subsidence of the whole countryside, which has resulted in 

 sinking the old river channel far below sea level, would tend 

 to preserve any carbonaceous matter thus brought in by 

 covering it with water. 



Objection may be taken to the assumption that the strata 

 could be so porous as to permit of the passage of water 

 carrying such quantities of peaty substance as are required 

 to account for the large amounts of carbonaceous matter 

 now found in the country. But when we consider that the 

 lignite is found in the most broken part of the whole 

 formation, where it has been crumpled into short folds, 

 fractured by numerous cracks which have since become fines 

 of quartz reefs, dislocated by two main and several smaller 

 faults, and doubtless further disturbed by the recent move- 

 ments of elevation and subsidence to which the whole district 

 has been subjected, it is seen that unusual facifities would 

 doubtless be afforded for the passage of subterranean waters. 

 Here and there in the mines we come upon examples of free 

 passage of water through the broken rock. In one of the 

 branches of the West Tasmania reef the workmen followed 

 blocks and strings of quartz which were interspersed through 



