ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxsix 



each system — involves the hypothesis, that formations in one part 

 of the globe, which may, in general terms, he asserted to be the 

 equivalents of those in some very distant regions, were synchronous 

 with them in deposition, and to a degree of exactness which I cannot 

 but regard as exceedingly improbable in itself, and which cannot 

 possibly be established on direct geological evidence. This conclusion 

 of our author also involves, as I have before remarked, the dismem- 

 berment of local systems of lines of elevation (such, for example, as 

 those which exist in the south-east of England and in several of 

 our separate coal-fields, and other particular districts), presenting far 

 more obvious characters of unity than those systems into which 

 this theory would group them. Thus two faults or anticlinals, of 

 which the directions may differ by not more than 1 0° or 1 2°, though 

 the one may be an actual continuation of the other, must have 

 their family ties broken, and be respectively associated with 

 others of their class of very doubtful relationship. Proximity in 

 geological phsenomena, though not a necessary, is assuredly a pre- 

 sumptive proof of unity, and when uncontradicted by direct evidence, 

 must be received as a strong indication of it. A difficulty like that 

 which I am now discussing, might undoubtedly disappear before 

 exact and positive evidence, but, considering the necessary character 

 of geological evidence on such points, it must, I think, ever remain, 

 even under the most favourable circumstances, a grave obstacle to 

 the reception of the theory in the form in which it is now pro- 

 pounded. 



I have before remarked, that M. de Beaumont's theory must be 

 established or refuted by the observation of pheenomena and not by 

 abstract dynamical reasoning, but that geologists will still necessarily 

 look to its mechanical significance. The physical cause to which our 

 author refers the phsenomena of elevation — the shrinking of the 

 earth's crust — is that which appears to me most unlikely to produce 

 that paroxysmal action which his theory so essentially requires, and 

 most likely to produce those slow and gradual movements which it 

 scarcely recognizes. The actual depressions of the great oceanic 

 basins, and, generally, the more widely extended geological depressions 

 of the present or former periods, may, I think, be referred with great 

 probability to this cause ; but I feel great difficulty in tracing to it 

 the sudden and violent efforts required to produce paroxysmal move- 

 ments, for which explosive action, similar to the volcanic action of 

 the present time, though on a far larger scale, seems to me to offer 

 so much more satisfactory an explanation. The enormous outpouring 

 also of molten matter which must have accompanied the greater dis- 

 turbances of the earth's crust would seem thus to be more easily 

 explained, for the general tendency of the squeezing and compres- 

 sion of the crust must be to close and seal up those vents by which 

 molten matter might escape from beneath it. M. de Beaumont him- 

 self would seem to be aware that sudden collapses of the crust could 

 only be consistent with its extremely small thickness ; but I am sur- 

 prised at his adopting the hypothesis of its actual thickness not 

 much exceeding thirty miles, without any reference to the proof 



