268 KEY TO TERRESTRIAL HISTORY 



the consternation that might naturally have been expected. 

 Geologists did not offer much in the way of confutation, 

 but went on with their work and continued the identifica- 

 tion of strata by fossil remains : the chief effect, indeed, 

 appeared to be that logical persons who were not averse 

 to neologisms now began to say " homotaxial " when 

 formerly they would have used the word "contempo- 

 raneous." 



Nevertheless the polemic of Huxley struck at the very 

 root of the historical study of stratified rocks, and the 

 most important advance which this branch of our science 

 has made during the past twenty years is to be found in 

 its successful attempt to turn aside the blow. Before 

 considering the recent additions to our knowledge, let us 

 diverge for a moment to discuss one or two arguments 

 which might have been offered in defence, even without 

 more information than we possessed at the time this 

 address was delivered. 



Admitting unreservedly that contemporaneity cannot 

 be directly inferred from homotaxis, yet it may be possible 

 to connect them by some third term. Confining our atten- 

 tion in the main to the parallel systems of Europe and 

 North America, no one will deny that the deposits now 

 forming on each side of the Atlantic are both homotaxial 

 and contemporaneous, nor probably would even the most 

 captious critic think it worth while to dispute the con- 

 temporaneousness of the homotaxial gravels and alluvia 

 belonging to the so-called "recent" period of the two 

 continents. But immediately below these we find in both 

 hemispheres a series of beds known as Pleistocene : these 

 are undoubtedly homotaxial, are they also contempora- 

 neous? In both areas there is conclusive evidence to 

 prove that they were formed under glacial conditions of 

 climate : similar homotaxial deposits in Australia, 

 Tasmania, New Zealand, and South America prove the 



