Uniformity in Geological Change 



duction of others, as often as two formations in 

 contact are found to include dissimilar organic 

 fossils. But we must shut our eyes to the whole 

 economy of the existing causes, aqueous, igneous, 

 and organic, if we fail to perceive that such is not 

 the plan of Nature. 



I shall now conclude the discussion of the 

 question whether there has been any interruption 

 from the remotest periods, of one uniform and 

 continuous system of change in the animate and 

 inanimate world. We were induced to enter 

 into that enquiry by reflecting how much the pro- 

 gress of opinion in Geology had been influenced 

 by the assumption that the analogy was slight 

 in kind, and still more slight in degree, between 

 the causes which produced the former revolu- 

 tions of the globe, and those now in everyday 

 operation. It appeared clear that the earlier 

 geologists had not only a scanty aquaintance 

 with existing changes, but were singularly un- 

 conscious of the amount of their ignorance. With 

 the presumption naturally inspired by this un- 

 consciousness, they had no hesitation in deciding 

 at once that time could never enable the existing 

 powers of nature to work out changes of great 

 magnitude, still less such important revolutions 

 as those which are brought to light by Geology. 

 They therefore felt themselves at liberty to indulge 

 their imaginations in guessing at what might be, 

 rather than enquiring what is; in other words, they 

 employed themselves in conjecturing what might 

 have been the course of Nature in their own times. 

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