vii LAW AND PRINCIPLE 197 



the bonds, the relationships, which unite the ancient 

 organisms to one another and to living forms ; and they 

 have proved each type to be related by definite charac- 

 teristics to its ancestors on one side and its descendants 

 on the other, until finally the fossil remains of man appear 

 associated with those of animals, and with the flint 

 implements which represented the first weapons of the 

 human race. 



The use of fossils as convenient trade-marks by which 

 geological strata could be identified was established by 

 William Smith, but it was largely left to Gaudry to 

 show the genealogical relations of the different classes 

 of animals and their descent from primeval ancestors, 

 and thus to prove that evolution provides the reason for 

 particular fossils being found in particular geological 

 formations. " The stages of evolution of the fossils 

 which are brought to us for identification," he said, 

 " mark not only the modifications of organisation, but 

 also of the principal divisions of geological time. Taking 

 two different strata, if I find that in one the animals 

 indicate a condition of evolution less advanced than the 

 other, I conclude that the former are of the earlier age." 



Much remains to be done before the complete story 

 of the transformations of the animal kingdoms of the 

 past can be told, but it is upon the evolutionary plan 

 that all discoveries of fossil forms are recorded and all 

 modifications of structure interpreted. The history of 

 life is written on the rocks by fossil remains, and the 

 record shows that from the beginning there has been a 

 steady upward tendency. Taken as a whole, the plants 

 and animals of to-day are far more highly organised, 

 varied and beautiful than in the past ages of the world, 

 and the future will probably see still higher forms of 

 life. But what of the beginning ? Evolution is not 



