ANNIVERSARY ADDRESS OF THE PRESIDENT. IxXV 



discussing these theories with reference to my own definitions of the 

 terms which designate them, and which others may not have accepted 

 in the same rigorous sense. Still I believe that, if they are to bear 

 a determinate meaning, they must ultimately be received in the sense 

 which I have assigned to them. In that sense, leaving the question 

 entirely open respecting the organic creation to be decided by future 

 research, I feel it impossible to adopt any other view than that of 

 progressive development of inorganic matter from some primitive to 

 its present state. I have already remarked that we do not know 

 sufficient of the laws which may regulate the succession of organic 

 life on our planet, to assert that the one of these theories or the other 

 is most consistent with these laws ; but, with respect to inorganic 

 matter, the theories of uniformity and of non-progression appear 

 to me incompatible with our most certain knowledge of the properties 

 of heat — that ever-active agent in the work of terrestrial trans- 

 formation. 



It is far from my purpose to enter into a discussion of the evidence 

 which might be deduced from recognized geological phsenomena in 

 favour of the theory of progression, but merely to insist on that which 

 depends on the most immediate and simple inferences from the pro- 

 perties of heat. And here it should be remarked, that this argument 

 cannot be refuted by any reasoning which may appear to establish 

 an approximate general uniformity or non-progression in the character 

 of geological phsenomena since the earliest geological epochs, because 

 the progressive refrigeration of the earth from some high temperature 

 to its present temperature is perfectly consistent with such approxi- 

 mate uniformity or non-progression for enormous periods of time. 

 Climatal conditions, for instance, may, consistently with the earth's 

 continual refrigeration, have remained sensibly unaffected by the in- 

 ternal heat, as I have elsewhere explained, for millions of centuries ; 

 and the very theory which tells us that these conditions can never 

 be sensibly altered in all future time (external circumstances remaining 

 the same) essentially involves the hypothesis of progressive change 

 towards an ultimate limit. 



The contributions which we have received on the geology of the 

 Secondary and Tertiary formations have not been numerous. I shall 

 restrict myself to the brief notice of a paper by Professor E. Forbes, 

 and one by his Grace the Duke of Argyll. The former is entitled 

 " On the Estuary Beds and the Oxford Clay at Loch Staffin in 

 Skye." 



Sir R. Murchison, in a paper read by him before the Society in 

 1827, containing remarks on the strata of the north of Scotland, men- 

 tions his having found species of Cyclas, Paludina, Neritina, Ostrea, 

 and Mytiliis, in flattened masses or blocks of shelly limestone, on 

 the shores of Loch Staffin, in the northern part of the Isle of Skye. 

 Two species of the Cyclas, the Paludina, and the Ostrea were at 

 that time considered identical with the fossils of one of the upper 

 beds of the Weald Clay in the South-east of England, to which forma- 

 tion, therefore, it was naturally inferred, the blocks, in which these 

 fossils existed, might belong. Prof. E. Forbes found similar blocks on 



