xii,] THE GENEALOGY OF ANIMALS. 311 



in the middle of the Silurian series, extensive uncon- 

 formity of the strata indicates the lapse of vast intervals 

 of time between the deposit of successive beds, without 

 any corresponding change in the Fauna. 



Professor Haeckel will, I fear, think me unreasonable, 

 if I say that he seems to be still overshadowed by geo- 

 logical superstitions ; and that he will have to believe 

 in the completeness of the geological record far less than 

 he does at present. He assumes, for example, that there 

 was no dry land, nor any terrestrial life, before the end 

 of the Silurian epoch, simply because, up to the 

 present time, no indications of fresh water, or terrestrial 

 organisms, have been found in rocks of older date. 

 And, in speculating upon the origin of a given group, 

 he rarely goes further back than the "Ante-period," 

 which precedes that in which the remains of animals 

 belonging to that group are found. Thus, as fossil 

 remains of the majority of the groups of Reptilia are 

 first found in the Trias, they are assumed to have 

 originated in the " Antetriassic " period, or between the 

 Permian and Triassic epochs. 



I confess this is wholly incredible to me. The Per- 

 mian and the Triassic deposits pass completely into one 

 another ; there is no sort of discontinuity answering to 

 an unrecorded " Antetrias ; " and, what is more, we have 

 evidence of immensely extensive dry land during the 

 formation of these deposits. We know that the dry land 

 of the Trias absolutely teemed with reptiles of all groups 

 except Pterodactyles, Snakes, and perhaps Tortoises ; 

 there is every probability that true Birds existed, and 

 Mammalia certainly did. Of the inhabitants of the 

 Permian dry land, on the contrary, all that have left a 

 record are a few lizards. Is it conceivable that these last 

 should really represent the whole terrestrial population 

 of that time, and that the development of Mammals, of 



