214 LIFE ON THE EARTH. 



bro-Silurian series, not only lived long before but 

 must have lived somewhere else. But as in all the 

 known examples of this series of strata, wherever 

 found, we have everywhere animals of the same 

 general type, and nowhere the traces of earlier pro- 

 genitors, it is clear that everywhere we are required 

 by the hypothesis to look somewhere else; which 

 may fairly be interpreted to signify, that the hypo- 

 thesis everywhere fails in the first and most im- 

 portant step. How is it conceivable that the second 

 stage should be everywhere preserved, but the first 

 nowhere? 



This difficulty occurs again and again, not only 

 at the great breaks of the series of strata accom- 

 panied with much disturbance and change of sea- 

 bed, but during the ordinary and least interrupt- 

 ed accumulations of deposit, for example, in the 

 Silurian and Oolitic systems, in each of which new 

 families and genera, new types of structure in short, 

 make their appearance frequently at definite stages, 

 and always compel the hypothesis to the same an- 

 swer look elsewhere for the progenitor the father 

 is never buried with his children. 



Is there not at the base of all these hypotheses 

 of one continuously branching stream of variable life, 

 some trace of the common errors of assuming that to 

 be true without limits, which is acknowledged to be 



