189 



his powerful mind to the promotion of physical truth ; and we have 

 to lament the loss of a name which has long decorated the list of 

 our Foreign Members. A proper homage has been already paid, 

 by the President of the Royal Society, to the memory of this illus- 

 trious person; whose labours, however great the light they shed on 

 our department of natural history, were still more nearly connected 

 with exact science. 



Several of the Papers read at our meetings, between the last 

 Anniversary and our separation for the summer, have through 

 different channels already come before the public. It would have 

 been well, that at least a part of them should have appeared in our 

 Transactions. But our funds have not always admitted of a suffi- 

 ciently rapid publication to meet the wishes of those authors who 

 have most original matter to communicate. This is a subject of 

 regret, and well deserves the consideration of the Council for the 

 coming year. The Transactions of the Society form unquestion- 

 ably the most honourable official record of our labours. It is 

 through them that we are represented in the great republic of 

 science ; and without them, beyond our own immediate circle, we 

 possess neither voice nor animation. 



The progress of our body in geological inquiry since the former 

 Anniversary, will be best understood by glancing over the various 

 memoirs which have been the subject of discussion at our meetings. 

 It will be useless to do this in the exact order in which they came 

 before us; I shall therefore follow that order in which the subjects 

 themselves appear to be naturally connected with each other. 



Our attention has been several times called to the theory of the 

 excavation of valleys, and to the effects produced by river currents 

 in modifying the form of the solid parts of the earth. The subject 

 was introduced during the former year by a memoir of Messrs. 

 Lyell and Murchison, on certain portions of the volcanic regions 

 of Central France; in which they show (in accordance with the 

 views of Montlosier, Scrope, and some other authors) that the ex- 

 isting rivers have, by a long continued erosion, eaten out deep 

 gorges, not only through currents of basaltic lava which have 

 flowed through the existing valleys, but also through solid rocks 

 of subjacent gneiss. They further prove, on evidence which to 

 me seems not short of demonstration, that no great denuding wave 

 or mass of water lifted by supernatural force above its ordinary 

 level, could have assisted in forming such denudations : for the 

 country is still studded with domes of incoherent matter, the rem- 

 nants of former craters ; from which may be traced, continuously, 

 streams of lava, intersected in the courses of the rivers by these 

 deep gorges — the gages and tests of the erosive power of running 

 water during times comparatively recent. 



The elaborate Paper of Mr. Conybeare on the valley of the 

 Thames is still fresh in our recollection. He proves that the ero- 

 sive power of the river has, within the records of history, produced 

 no effect on the general features of the country through which it 



B 



