Dr. Mac Culloch on the Parallel Roads of Glen Roy. 359 



rected 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 y 

 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 au 

 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 al- 

 ready considered the other modifications which the action of water 

 flowing through a channel of varying breadth and figure must re- 



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