lxXVlii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May I9IT, 



elevation, and with tectonic structures and movements subsequently 

 produced, and thence even with lines of drainage. 



Information on the buried extension of strata is more difficult to 

 obtain, and it can only be got when folds or faults have broken the 

 course of the regular structure, allowing the agents of denudation 

 to lay bare a far larger sequence of formations than usual, or where 

 deep drilling has been carried out. There is perhaps hardly a single 

 deep boring in the country which has not yielded important in- 

 formation as to the variation of some stratum or other in a direction 

 not coincident with its outcrop. Evidence is given of the thinning 

 and disappearance of strata, of their change in grain, in organisms, 

 and in relation to, beds above and below. Whether these borings 

 succeed or fail in their primary economic purpose, their value to the 

 geologist is incalculable ; and I would again urge, as on more than 

 one previous occasion, Jthat the information which they give should 

 be preserved with the most jealous care. Not only detailed and 

 tabulated records, but actual rock-specimens should be collected 

 and kept ; and, even though the information yielded may have in 

 some cases to be locked up in confidence for a generation or more, 

 that information will eventually be available for generalization. 

 The confidence engendered by the administration and personnel of 

 the Geological Survey has, I am glad to say, borne abundant fruit in 

 this direction, and we may trust that an increasing flow of records of 

 this invaluable information will continue to be stored in the Survey 

 Office for the use of present and future geologists. It is even to be 

 hoped that at some future time, both for economic and for purely 

 scientific reasons, borings may be carried out at carefully selected 

 spots, not only to elucidate underground structure and its bearings 

 upon the distribution of deposits of economic value, but even to 

 settle doubtful points of scientific interpretation. 



The part of any formation which extends and is hidden beneath 

 the sea presents even greater difficulties, and it is improbable that 

 we shall ever possess more than inferential information about the 

 large area of the earth's surface covered by the hydrosphere. It is 

 true that lines of borings have been carried out across narrow and 

 shallow seas, and a daring success was made of the lagoon-boring 

 at Funafuti ; but for the most part we shall have to obtain our 

 knowledge of the origin and history of the greater features of the 

 earth from observations made upon what are land-masses at the 

 present time. Still, portions of areas which were until recently 

 covered by the sea, but the surfaces of which have been raised above 

 its level by deposits of drift, ice, coral, or other recent marine deposits, 



