When we examine the stones and gravel of which it is composed, these
appear to have belonged to the vertical strata or schistus mountains.
They are in general the hard and solid parts of those indurated
strata, worn and rounded by attrition; particularly sand or marl-stone
consolidated and veined with quartz, and many fragments of quartz, all
rounded by attrition. In this pudding-stone of the Jed, I find also
rounded lumps of porphyry, but have not perceived any of granite.[32]
This however is not the case in the pudding-stone of the schistus
mountains, for, where there is granite in the neighbourhood, there is
also granite in the pudding-stone.
[Note 32: A view of this object is seen in plate 3d. It is from a
drawing taken by Mr Clerk of Eldin.]
From this it will appear, that the schistus mountains or the vertical
strata of indurated bodies had been formed, and had been wasted and worn
in the natural operations of the globe, before the horizontal strata
were begun to be deposited in those places; the gravel formed of those
indurated broken bodies worn round by attrition evince that fact.
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