266 KEY TO TERRESTRIAL HISTORY 



for one, had little mercy on the rough-and-ready methods 

 of geologists, and seriously lectured them on what he 

 regarded as their illogical procedure. Huxley was no 

 less emphatic, and adopting an argument first employed 

 by Edward Forbes, boldly asserted that the presence of 

 similar fossils in strata of distant parts of the world such, 

 say, as those of the Silurian of North America on the one 

 hand and of England on the other so far from proving 

 an identity in age, points rather in a contrary direction, 

 and suggests a difference in age. Eor these fossils are not 

 merely signs by which a rock may be identified, they are 

 the remains of organisms, and, as such, must have come 

 into existence at some definite place and at some definite 

 time : each species must have arisen as Edward Forbes 

 phrased it at some centre of creation. The descendants 

 of the original species issuing forth from this centre, peopled 

 the surrounding seas, and wandered, generation after 

 generation, further and further away from their original 

 home, till, after a long lapse of time, they found a grave 

 in distant parts of the world. Thus, if \ve assume some 

 Silurian species to have had their origin in the neighbour- 

 hood of Dudley, a long period might have elapsed before 

 their descendants reached in their migrations the shores 

 of North America, and consequently the presence of these 

 species in* sediments on opposite sides of the Atlantic 

 would be a proof, not of the identity, but of the difference 

 in age of these deposits. Huxley proceeded further, and put 

 the cause more strongly still, asserting that "for anything 

 geology and palaeontology are able to say to the contrary, 

 a Devonian fauna and flora in the British Isles may have 

 been contemporaneous with Silurian life in North America, 

 and with a Carboniferous fauna and flora in Africa." 

 " Not proven and not provable" is the verdict he records 

 against all the grand hypotheses of the palaeontologist 

 respecting the general . succession of life on the globe. 



