42 NOTES ON THE MOUNT LYELL DISTRICT, TASMANIA. 



and Owen, how do my opponents account for its parallelism to 

 the sea coast, and 'its steep slopes away from the sea ; 

 and why have the mountains that dragged out appear- 

 ance and broken surface ? Will not the phenomena 

 observed be accounted for equally as well, if not better, by 

 the views I have expressed than by the simple contraction 

 theory ? The pressure of water on the bottom and sides of a 

 vessel containing it is well known ; the force of the tides 

 and currents is also appreciated. The effect of the rotation 

 of the earth tending to throw objects towards the 

 east is felt by our express trains and ocean boats, as is also 

 that of winds ; the shape of waves of water or sand is 

 familiar as having the steeper side away from the force pro- 

 ducing them ; where, then, is the absurdity of accrediting the 

 ocean with being the greatest auxiliary to the contraction of 

 the earth in mountain building ? Mounts Lyell and Owen 

 show no signs of having been caused by simple denudation; 

 there is no indication of there ever having been sufficient 

 water to cut out the Linda Valley. The conglomerate cap- 

 ping this range was deposited before the mountains were 

 raised, and most of the gravel in the Linda Valley is due to 

 the weathering of the conglomerate, which was cracked and 

 broken as the peaks raised their heads at the expense of the 

 surrounding neighbourhood, for an inclined surface has a 

 greater superficial area than a horizontal one. 



Concerning the so-called fissure lodes, I consider the term 

 as generally used misapplied. In our text books we find 

 the fissure theory upheld. My old professor at the Clausthal 

 School of Mines, Herr Dr. Bergrath v. Groddeek, states in 

 his work on Lagerstattenlehre, " Gauge sind ausgefiillte 

 Spalten," V. Cotta m his book writes:—" Since, according to 

 our definition, all true lodes are aggregates of mineral matter 

 in fissures, fissures must necessarily have first been formed and 

 then filled. Both operations may have been independent of 

 each other, and even when this is probably not the case still 

 the formation of the fissure was an entirely different opera- 

 tion from that of their being filled with mineral matter." 



Without disparaging text books, from which we learn the 

 A B C of sciences, we really get more information from 

 original articles and discussions on the same by men who have 

 made researches from all points of view. Thus Mr. S. F. 

 Emmons, one of the ablest lining authorities on ore deposits, 

 states that: — "Many deposits formerly supposed to have 

 been deposited in open cavities have really been formed by 

 metasomatic interchange of ore with country rock, e.g., lead 

 ore in limestone formations, Leadville, U.S.A. Very many 

 so-called fissure veins in crystalline rocks are formed by per- 

 colation water circulating along joints and shrinkage cracks, 

 fault planes or zones of crushed rock, which have filled the 



