Fig. 10. 
(Quartz Reef, Erlstoun, Mt. Margaret Goldfield. 
A great deal has been written during the last decade or two 
on the matter of ore deposits, mostly however, on more or less 
isolated occurrences, which detract very considerably from the 
value they would otherwise have had, and many of the later day 
theories on ore deposition have been based not so much upon the 
results of careful observation, as upon speculation, which has re- 
sulted in one eminent scientist giving utterance to the dictum that 
■‘Mining prophesies are proverbially erroneous.” Very few 
mines present data sufficient to enable a true mental pic- 
ture of the real nature of an ore deposit to be oljtained, such 
can, however, only be arrived at by careful inve,stigation into the 
geological structure and stratigraphy of wide stretches of country, 
where all the ore de])osits are perhaps genetically connected and 
capable of throwing light one upon another. 
Since the days of Daiibree work in experimental geology has 
fallen somewhat into desuetude. A wide and almost un- 
trodden held (in Australia at any rate) is open for 
laboratory research and experimental work, in connection 
with the genesis of minerals and the rock types of which 
they form an integral part. \\'(')rk of this kin<l. owing to the 
light which the results when i)roperly interpreted, would tend to 
throw on the peculiarities of the distribution of metalliferous ores, 
etc., can readilv be seen to be of considerable economic importance. 
The recent experimental work upon silicate mixtures, carried out 
in the geophysical laboratory at Washington may be cited as evi- 
dence of the value of such investigations in connection with the 
two most im])ortant ]>roblems with which the geologist has to deal. 
