Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/369

 from the east. If we even imagine it directed from the west it must have failed to make the impressions there existing on the right side, or the cul de sac would at least, have been filled with loose materials.

In describing the openings by which Glen Turit and Glen Fintec communicate with Glen Roy, I pointed out a circumstance of which I meant to make use in this argument. I remarked that the bottom of Glen Fintec rose to such a height as to exclude the lower line, and that the bottom of Glen Turit was so high, at no great distance from its entrance into Glen Roy, as to exclude the whole three. With regard to the former I believe that it consists of rock, and cannot therefore have gained its present height by the deposition of alluvial matter posterior to the time at which the lines were formed: with regard to Glen Turit I am certain of this fact. It is plain therefore that no current could have flowed from Glen Roy through Glen Fintec at the level of the lowermost line, nor through Glen Turit at that of any of the three; yet the lines are impressed on the sides almost to the very point where they meet the elevated bottoms of these glens; an effect which, on the supposition of a current, would be impossible. The rocky nature of the bottom of Glen Turit also proves, as far as this valley is concerned, that its former was like its present state; or at any rate, that it has not been elevated by an alluvial deposit since the supposed flowing of the waters; the only supposition which could affect the validity of the argument that I have attempted to deduce from it.

It is in the next place necessary to inquire in what respect the effects of a deluge can be made to correspond with the absolutely level position which the lines of Glen Roy present; as I have already considered the other modifications which the action of water flowing through a channel of varying breadth and figure must receive.