Masterpieces of Science 



fauna of these last-mentioned formations wanted 

 the connecting links which now render the pas- 

 sage from the one to the other much less abrupt. 

 In like manner the Upper Miocene has no repre- 

 sentative in England, but in France, Germany, 

 and Switzerland it constitutes a most instructive 

 link between the living creation and the middle 

 of the great Tertiary period. Still we must ex- 

 pect, for reasons before stated, that chasms will 

 forever continue to occur, in some parts of our 

 sedimentary series. 



CONCLUDING REMARKS ON THE CONSISTENCY OF 



THE THEORY OF GRADUAL CHANGE 



WITH THE EXISTENCE OF GREAT 



BREAKS IN THE SERIES 



To return to the general argument pursued in 

 this chapter, it is assumed, for reasons above 

 explained, that a slow change of species is in 

 simultaneous operation everywhere throughout 

 the habitable surface of sea and land; whereas 

 the f ossilization of plants and animals is confined 

 to those areas where new strata are produced. 

 These areas, as we have seen, are always shifting 

 their position, so that the fossilizing process, by 

 means of which the commemoration of the par- 

 ticular state of the organic world, at any given 

 time, is effected, may be said to move about, 

 visiting and revisiting different tracts in succes- 

 sion. 



To make still more clear the supposed working 

 128 



