IN LOWEST FOSSILIFEROUS STRATA. 319 



been wholly obliterated by metainorphic action, for if this had 

 been the case we should have found only small remnants of 

 the formations next succeeding them in age, and these would 

 always have existed in a partially metamorphosed condition. 

 But the descriptions which we possess of the silurian deposits 

 over immense territories in Russia and in North America, do 

 not support the view that the older a formation is, the more 

 invariably it has suffered extreme denudation and metamor- 

 phism. 



The case at present must remain inexplicable, and may be 

 truly urged as a valid argument against the views here enter- 

 tained. To show that it may hereafter receive some expla- 

 nation, I will give the following hypothesis. From the 

 nature of the organic remains which do not appear to have in- 

 habited profound depths, in the several formations of Europe 

 and of the United States ; and from the amount of sedi- 

 ment, miles in thickness, of which the formations are com- 

 posed, we may infer that from first to last large islands or 

 tracts of land, whence the sediment was derived, occurred in 

 the neighborhood of the now existing continents of Europe 

 and North America. This same view has since been main- 

 tained by Agassiz and others. But we do not know what 

 was the state of things in the intervals between the several 

 successive formations ; whether Europe and the United 

 States during these intervals existed as dry land, or as a 

 submarine surface near land, on which sediment was not 

 deposited, or as the bed of an open and unfathomable sea. 



Looking to the existing oceans, which are thrice as exten- 

 sive as the land, we see them studded with many islands ; but 

 hardly one truly oceanic island (with the exception of New 

 Zealand, if this can be called a truly oceanic island) is as yet 

 known to afford even a remnant of any palaeozoic or secondary 

 formation. Hence, we may perhaps infer, that during the 

 palaeozoic and secondary periods, neither continents nor con- 

 tinental islands existed where our oceans now extend ; for 

 had they existed, palaeozoic and secondary formations would 

 in all probability have been accumulated from sediment de- 

 rived from their wear and tear ; and these would have been 

 at least partially upheaved by the oscillations of level, which 

 must have intervened during these enormously long periods. 

 If, then, we may infer anything from these facts, we may 

 infer that, where our oceans now extend, oceans have ex- 

 tended from the remotest period of which we have any record ; 

 and on the other hand, that where continents now exist, large 



