210 SUPERPOSITION NOT PARENTAL RELATION. 



their conclusion, should have been thus a mere effect of ac- 

 cident. Accident has its laws, but uniformity is not one ol 

 them ; and should the experience be invariable, as it already 

 seems extensive, that immediately beneath the fucoidal beds 

 organic remains cease, I do not see how the conclusion is to 

 be avoided, that they represent the period in which at least 

 existences capable of preservation were first introduced. Every 

 case of coincident cessation which has occurred since the de- 

 termination of the second case must be reckoned, not simply 

 as an additional unit in evidence, but, on the principles which 

 determine mathematical probability, as a unit multiplied, first 

 by the chances against its occurrence, regarded as a mere con- 

 tingency in that exact formation, and second, by the sum of 

 all the previous occurrences at the same point. 



In this curious question, however, which it must be the 

 part of future explorers in the geological field definitely to 

 settle, the Lamarckian can have no legitimate stake. It is 

 but natural that, in his anxiety to secure an ultimate retreat 

 for his hypothesis, he should desire to see that darkness in 

 which ghosts love to walk settling down on the extreme verge 

 of the geological horizon, and enveloping in its folds the first 

 beginnings of life. But even did the cloud exist, it is, if I 

 may so express myself, on its nearer side, where there is light, 

 — not within nor beyond it, where there is none, — that the 

 battle must be fought. It is to Geology as it is known Co be, 

 that the Lamarckian has appealed, — not to Geology as it is 

 not known to be. He has summoned into court existing 

 witnesses ; and, finding their testimony unfavourable, he 

 seeks to neutralize their evidence by calling from the " vasty 

 deep" of the unexamined and the obscure, witnesses that 

 *' won't come," — that by the legitimate authorities are not 

 known to exist, — and with which he himself is, on his own 

 confession, wholly unacquainted, save in the old scholastic 

 character of mere possibilities. The possible fossil can have 



