OF THE EARTH. 467 



the negative. It is something, to have traced even 

 an inanimate globe through such a series of changes ; 

 to have arrived at that which is, to us, the com- 

 mencement of all order. On what existed before 

 that period, we may form conjectures, but we can 

 reason no longer: they who choose, may imagine 

 even prior revolutions ; since it might be supposed 

 that the strata of the most distant earth, thus pointed 

 out, must have been produced from a still prior si- 

 milar one. But where evidence ceases, the limits of 

 sound philosophy are drawn. The last globe that we 

 can trace, is, to us, the primordial one. Beyond, is 

 the region of hypothesis : it is for this to speculate 

 on what preceded, and to fix the period of absolute 

 Creation. 



With respect to the nature and causes of the revo- 

 lutions belonging to these remote conditions of the 

 globe, we can but argue from general analogy, and 

 thus presume that they resembled the later ones re- 

 specting which we possess evidence. Yet we are not 

 absolutely deprived of some evidence as to the causes ; 

 since the fragments of granite in the micaceous schist 

 are sufficient to prove that the strata immediately an- 

 terior to our primary ones had been elevated by this 

 substance, just as these have been. 



It was necessary to commence from the primary 

 strata, and to conduct this enquiry retrogressively ; 

 because the only evidence of the earliest conditions of 

 the earth consists in their constitution. But I must 

 return to the same point, for the purpose of tracing 

 forwards, or to later periods, the revolutions suc- 

 ceeding to that which first elevated the primary strata 

 from the bottom of the ocean. It must be remem- 

 bered however, that the term primary is here used in 

 its accepted sense, as a conventional distinction, 



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