vni. 



THE PARALLEL ROADS OF GLEN JROK> 



THE first published allusion to the Parallel Roads of 

 Grlen Roy occurs in the appendix to the third volume of 

 Pennant's ' Tour in Scotland,' a work published in 1776. 

 * In the face of these hills,' says this writer, ' both sides 

 of the glen, there are three roads at small distances 

 from each other and directly opposite on each side. 

 These roads have been measured in the complete parts 

 of them, and found to be 26 paces of a man 5 feet 10 

 inches high. The two highest are pretty near each 

 other, about 50 yards, and the lowest double that 

 distance from the nearest to it. They are carried along 

 the sides of the glen with the utmost regularity, nearly 

 as exact as drawn with a line of rule and compass.' 



The correct heights of the three roads of Grlen Roy 

 are respectively 1150, 1070, and 860 feet above the 

 sea. Hence a vertical distance of 80 feet separates the 

 two highest, while the lowest road is 210 feet below the 

 middle one. 



These ' roads ' are usually shelves or terraces formed 

 in the yielding drift which here covers the slopes of the 

 mountains. They are all sensibly horizontal and there- 

 fore parallel. Pennant accepted as reasonable the 

 explanation of them given by the country people in his 



1 A discourse delivered at the Boyal Institution of Great Britain 

 on June 9, 1876. 



