ANNIVERSARY ADDRESS OF THE PRESIDENT. 73 



physical and biological evidence, to arrive at something like certain 

 conclusions concerning the exact conditions under which various 

 geological formations have been accumulated; for at present our 

 speculations upon the subject are often little better than hajjhazard 

 guesses. 



The conditions which must have prevailed during the deposition 

 of a particular bed having been determined, the present state of 

 mineralization of the organic remains becomes a subject of very 

 interesting study ; for here we may find a clue which will enable 

 us to unravel the series of physical and.chemical changes which must 

 have gone on in the mass, since the first accumulation of its mate- 

 rials. In cases of difficulty of this kind, the nature and degree of 

 alteration of a shell or bone, of which the original composition is 

 known, becomes an especially valuable piece of evidence. 



I am convinced that the future progress of geological thought is 

 closely bound up with the increase of our knowledge concerning 

 the conditions under which the various forms of marine life flourish, 

 and under which their remains become imbedded in sedimentary 

 deposits ; though what has been already accomplished in this 

 direction, it must be admitted, is but small, and much of it will have 

 to be done over again. 



We hear much — far too much, as I think — at the present day of an 

 " irrational Uniformitarianism." Is not the real source of danger 

 in an exactly opposite direction ? Does not the irrationality 

 characterize him who, without attempting to obtain a more complete 

 knowledge of the processes going on during the original deposition 

 and subsequent changes of rock-masses, is ready, as each new 

 difficulty presents itself, to fall back upon some old discredited 

 Deus ex machind in the form of deluges of water, floods of fire, 

 boiling oceans, caustic rains, or acid-laden atmospheres ? 



Considering how little we as yet know of many of the conditions 

 under which deposits are being formed at the present day, and remem- 

 bering how large a part of the little we do know has been acquired 

 within the last few years, we might pause before declaring that 

 the path upon which Geology entered in earnest only some fifty years 

 ago is a wrong one, and that the sooner we begin to retrace our 

 steps the better. 



Can we even now be in danger of forgetting that " Slough of 

 Despond," wherein the geologist, laden with a grievous burden of 

 traditional assumptions and irrational theories, so long and so hope- 

 lessly floundered, till one Help pointed out a way of escape, and 



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