GEOLOGICAL SPRING-TIME. 291 



Already, in the work, it has been seen that the transformation 

 of the crust of the earth did not proceed in a uniform manner, 

 but that long periods of comparative repose were followed by 

 great revolutions (supra, p. 250). In the process of develop- 

 ment of organic nature the same phenomenon is met with, so 

 that there is a correlation between the transformation of the 

 crust of the earth and the evolution of organic nature. 



Switzerland in the Pliocene epoch obtained its present con- 

 figuration, and in the same period the chain of the Caucasus 

 and the range of the Himalayas were upheaved. A large por- 

 tion of the globe must, consequently, have been affected by this 

 revolution immediately after the Pliocene in the Quaternary 

 period, and the transformation also occurred of organic nature 

 which has ever since retained the same characteristics. 



Phenomena of the same kind are recognized in the Flysch 

 formation, which is almost destitute of animals, in the upheaval 

 of land at the close of the Jurassic period increasing the size of 

 continents (vol. i. p. 174), and in the stormy Permian period 

 which terminated the Carboniferous epoch. Hence there were 

 times during which these transformations took place over vast 

 districts ; they were carried on with sufficient rapidity, and they 

 gave rise to more general and more decided changes. 



Times of creation occurred during which was accomplished a 

 remoulding of organic types, and there was a primaeval epoch 

 during which the first species were brought into being. Even 

 if the first species were extremely simple, for them an act of 

 creation must be admitted, an act without example in modern 

 times; for in our days plants and animals of decidedly low 

 forms proceed from species already in existence. 



Such periods of creation may be termed a geological spring- 

 time, thus alluding to the succession of the seasons and recall- 

 ing the law of periodicity, which may have been exerted in the 

 renewal of organic nature. But the circle influenced by this 

 law is so vast that human intellect cannot appreciate either its 

 height or its extent. No means are afforded to determine with 

 certainty these epochs of creation. 



Great creative renewals are indicated within the limits of 

 the principal geological periods ; and during those periods im- 

 portant transformations also took place, the significance of 



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