IV THE GENEALOGY OF ANIMALS 117 



interposes a period before each, as an &quot; Antetrias 

 zeit,&quot; &quot;Antejura-zeit,&quot; &quot; Antecreta-zeit,&quot; &quot;Anteo- 

 cenzeit,&quot; &c. And he conceives that the abrupt 

 changes between the Fauna? of the different forma 

 tions are due to the lapse of time, of which we have 

 no organic record, during their &quot; Ante-periods.&quot; 



The frequent occurrence of strata containing 

 assemblages of organic forms which are inter 

 mediate between those of adjacent formations, is, 

 to my mind, fatal to this view. In the well- 

 known St. Cassian beds, for example, Pabeozoic 

 and Mesozoic forms are commingled, and, between 

 the Cretaceous and the Eocene formations, there 

 are similar transitional beds. On the other hand, 

 in the middle of the Silurian series, extensive 

 unconformity 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 unreason 

 able, if I say that he seems to be still overshadowed 

 by geological 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 indica 

 tions 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 



