C) 



C— GEOLOGY. 79 



tions. For purposes of domestic water supplies, where the district is 

 lacking in surface water, and for indicating the nature of the soil, subsoil 

 and underlying rocks for the excavation of trenches, earthworks and other 

 purposes, the assistance of the geologist is most desirable, and this fact 

 is now thoroughly recognised by military authorities. The supply of 

 water that has to be transported long distances means great loss of time 

 and opportunity, whereas geological advice can often enable it to be 

 obtained on the spot by the sinking of shallow wells. 



Geological Reports. — For the preparation of departmental reports on 

 the physical features and geology of a young country— one that is for the 

 special use of officials who may not be familiar with scientific or technical 

 terms- — it is desirable that language as simple as possible should be used 

 in describing the various features. There are many scientific terms that 

 are necessary to express what is desired, but it is advisable, when using 

 them, to have accompanying explanations in parentheses, or a separate 

 glossary, to which reference can be made. Whenever possible, however, 

 it is preferable to avoid such terms, which are suitable only for a purely 

 scientific report. 



Aerial Survey. — A few words may be said on the use of the aeroplane 

 — and hydroplane where suitable — for a knowledge of the broad topo- 

 graphical features such as the courses of streams, the nature of the drainage, 

 hills, ranges, plains, and lakes of a country, and the assistance given to 

 geological determination by that means. It is well known that certain 

 rock masses weather with characteristic features. The geologist with 

 ground experience of such will soon obtain aerial experience of the 

 same, especially if during his flights he takes photographs from various 

 angles and altitudes. This is particularly useful for open country where 

 no thick forest hides the terrestrial features from view. A recon- 

 naissance of this kind yields much valuable physiographic information of 

 the country in a small fraction of the time required to traverse the same 

 area by terrestrial means. It shows the routes by which the geological 

 features can best be ascertained by the usual modes of transport on land. 

 These planes also aid greatly in the transport of men and material. 



Geophysical Prospecting. — Modern science has shown that a great deal 

 of assistance can now be obtained by mechanical means, based on certain 

 physical laws. The methods are the gravimetric, magnetic, seismic, 

 acoustic or sonic, and electrical. They have now been tested and improved 

 so much that the presence and approximate positions of bodies of certain 

 substances below the surface of the ground — and of which there is no visible 

 evidence — can be determined by their application. 



These methods involve costly apparatus, high training, much time, 

 expense and suitable conditions, both terrestrial and climatic, before they 

 can be fully utilised, but of their importance and use there is no question 

 of doubt. How far they can be applied to a young countrj' depends upon 

 natural conditions and the financial assistance available. 



Examples of Benefits to Colonies from Survey Discoveries. 



In order that a clear impression may be gained of the practical results 

 following the activities of these surveys in Colonies a few remarks may 

 be made regarding the development of certain mineral deposits dis- 



