THE IMPERFECTION OF THE GEOLOGICAL RECORD 277 



going; namely, from the several formations being separated 

 from each other by wide intervals of time. This doctrine has been 

 emphatically admitted by many geologists and palaeontologists, 

 who, like E. Forbes, entirely disbelieve in the change of species. 

 When we see the formations tabulated in written works, or when 

 we follow them in nature, it is difficult to avoid believing that 

 they are closely consecutive. But we know, for instance, from 

 Sir R. Murchison's great work on Russia, what wide gaps there 

 are in that country between the superimposed formations; so it 

 is in North America, and in many other parts of the world. The 

 most skilful geologist, if his attention had been confined exclu- 

 sively to these large territories, would never have suspected that 

 during the periods which were blank and barren in his own coun- 

 try, great piles of sediment, charged with new and peculiar forms 

 of life, had elsewhere been accumulated. And if, in every separate 

 territory, hardly any idea can be formed of the length of time 

 which has elapsed between the consecutive formations, we may 

 infer that this could nowhere be ascertained. The frequent and 

 great changes in the mineralogical composition of consecutive 

 formations, generally implying great changes in the geography 

 of the surrounding lands, whence the sediment was derived, ac- 

 cord with the belief of vast intervals of time having elapsed be- 

 tween each formation. 



We can, I think, see why the geological formations of each re- 

 gion are almost invariably intermittent; that is, have not fol- 

 lowed each other in close sequence. Scarcely any fact struck me 

 more when examining many hundred miles of the South American 

 coasts, which have been upraised several hundred feet within the 

 recent period, than the absence of any recent deposits sufficiently 

 extensive to last for even a short geological period. Along the 

 whole west coast, which is inhabited by a peculiar marine fauna, 

 tertiary beds are so poorly developed that no record of several 

 successive and peculiar marine faunas will probably be pre- 

 served to a distant age. A little reflection will explain why, along 

 the rising coast of the western side of South America, no ex- 

 tensive formations with recent or tertiary remains can anywhere 

 be found, though the supply of sediment must for ages have been 

 great, from the enormous degradation of the coast rocks and 

 from the muddy streams entering the sea. The explanation, no 

 doubt, is that the littoral and sub-littoral deposits are continu- 

 ally worn away, as soon as they are brought up by the slow and 

 gradual rising of the land within the grinding action of the coast 

 waves 



