336 Canadian Record of ScieTwe. 



arising. from the operation of a natural law, as it seems to 

 be, the continued action of the geyser must result in the 

 building up of a cylindrical cup-deposit, surrounded by 

 an overflow-deposit resembling a series of cased saucers 

 placed upside down with the bottom knocked out. 

 Whether the different physical and chemical conditions 

 under which the solvent in the cup and that which over- 

 flowed precipitated their solid materials, is sufficient to 

 account for the presence of gold in one deposit and its 

 absence (or scarcity) in the other, is a question which I 

 leave to chemists. As a matter of fact, this appears to 

 have been the case in Mount Morgan." 



" After the cessation of thermal activity, the powers of 

 sub-aerial denudation would come into play and might 

 carve down the hill till the line d. d. should represent the 

 surface contour of to-day. Such, I believe, is the history 

 of Mount Morgan as we now see it. Denudation would 

 obliterate the lateral terraces which are so familiar a 

 feature of the scenery of every important geyser district 

 in New Zealand and the Yellowstone, and which were 

 probably not absent from the slopes of Mount Morgan. 

 Mud pipes and other evidences of the outbreak of hot 

 water and gases from minor vents would be removed by 

 the same process." 



Since the report from which the above quotations were 

 taken, was written, some ten years have elapsed, and con- 

 tinuous work on a large scale has opened up and revealed 

 many additional details concerning this most interesting 

 ore body. 



The supposed " over-flow deposit " is now recognised by 

 Mr. Jacks as consisting merely of altered and weathered 

 portions of the country rock. 



So that Figure II. and also Figure I., so far as the 

 overflow deposit is concerned, although they have found 

 their way into scientific publications the world over, are 

 quite erroneous. The pipe also which Mr. Jack states to 



