Note 6 — Chapter I · (continued 2)
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Footnote 6:
(return)
The notion, that the water-worn gravel, which we so frequently find upon the surface of the earth, had been the effect of rivers transporting the rocks and stones, is not accurate or in perfect science. That stones are thus continually transported is certain; it is also indisputable, that in this operation they are broken and worn by attrition, more or less; but, that angular stones of the hardest substance are thus made into that round gravel, which we find so abundantly in many places forming the soil or loose materials of the surface, is a conclusion which does not necessarily follow from the premises, so far as there is another way of explaining those appearances, and that by a cause much more proportioned to the effect.
The view which I take of the subject is this; first, that those water-worn materials had their great roundness from the attrition occasioned by the waves of the sea upon some former coast. Secondly, that, after having been thus formed by agitation on the shores, and transported into the deep, this gravel had contributed to the formation of secondary strata, such as the puddingstone which has been described in Part I. Chap 5, and 6; and, lastly that it has been from the decay and resolution of those secondary strata, in the wafting operations of the surface, that have come those rounded siliceous bodies, which could not be thus worn by travelling in the longest river.