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There is one other point on which I must say a few words of caution, 

 respecting the relation of geological science to mining. Geologists are too 

 frequently called on to predict where mineral wealth may or may not 

 exist, but notwithstanding the great advances which have been made in 

 geology, we must admit that the science is still a mere digest of observed 

 phenomena, highly qualified to enable the student to observe and record with 

 accuracy, but not having yet attained to generalizations that warrant prediction 

 on this subject. A positive assertion that minerals exist in "such a district," 

 or "in such a direction," is very easily made and can never be positively 

 disproved. Tt is therefore quite safe, and likely to catch any credit that may 

 arise from future discoveries, but I am glad to say that it is rarely that true 

 science ventures on such predictions. It is very different in the case of a 

 positive assertion that a mineral does not exist in any particular locality, or, 

 that it cannot exist under certain conditions, which is a statement that should 

 only be ventured from actual observation, as it can, if incorrect, be at once 

 confuted. Geological science will not, therefore, enable us to dispense with 

 diligent and extended search. 



Before proceeding with the description of the localities where mines have 

 been opened, it is desirable that I should state briefly the leading features of 

 the geology of New Zealand. 



The whole group of islands may be looked on as a narrow mountain ridge, 

 rising from a deep ocean bed and extending in a N.N.E. and S.S.W. direction. 

 The form of the coast is determined by the outstanding bluffs of harder 

 primary formations, or by massive volcanic rocks that belong to the latest 

 Tertiary periods. These hard rocks, and especially those last mentioned, have 

 been the means of preserving patches of upper Secondary and Tertiary forma- 

 tions, which occupy a larger' proportional area in the North than in the South 

 island, where the mountains are loftier and occupy a greater breadth of country. 



We find, on a closer examination of the structure of the mountain system 

 thus described that it is by no means uniform throughout, but that the rocks 

 composing its southern portion are of much higher antiquity, and show evidence 

 of having been subjected to chemical changes at a greater depth in the earth's 

 crust. This difference is evidently due simply to the southern mountain mass 

 having been elevated to a greater extent as compared with the sea level, than 

 that in the north, and, in consequence, a much thicker layer of the superficial 

 and unaltered rocks has been removed by atmospheric denudation. A few 

 years since it might have seemed absurd to have attributed the present form 

 of mountains, thousands of feet high, traversed by valleys extending even 

 beneath the sea level, to denudation, or to have held that they are the mere 

 core of former mountains of greater magnitude, worn down by the long con- 

 tinued action of ice and running water. But now such a view is in accordance 

 with the best matured opinion. 



It is therefore to deficient elevation towards its northern extremity that 

 we must attribute the absence at the surface of many of the rock formations 

 which are prominent in the southern portion of New Zealand, and we must 

 conclude that in the north the same rocks exist at greater depths, and are 

 probably still undergoing chemical changes that have ceased to operate on 

 their southern equivalents. 



The sequence of geological formations in New Zealand is abruptly broken 

 about the close of the Lower Mesozoic period. 



All the formations prior to this have been, wherever they occur, more or 

 less cleaved and jointed, so as to be hardly distinguishable from the oldest 

 primary slates and sandstones, combined with which they constitute the main 

 part of the rocky framework of the islands, and form some of the highest 

 mountain peaks. 



BBB 



