OF THE EARN AND TEITH. 165 



the water was between 3 and 4 feet below the highest water-mark that could 

 be found ; while on Loch Lubnaig the difference was about 8 feet. How much 

 of this was due to the absolute depth of the water, and how much to the action 

 of the wind, I could not, of course, say. It was the western shore of the loch 

 in both cases where I took the measurements. But the striking thing is to 

 observe the closeness with which the results correspond with the proportions of 

 the old terraces. In the loch, where the floods and winds of the present day 

 raise the waters 3 to 4 feet, you have the old terrace about 14 feet high. In the 

 loch, where the waters at present are raised some 8 feet, you have the old 

 terrace lying 37 feet high. It is hardly possible to resist the inference that 

 these old terraces are due simply to the greater flooding power of some former 

 epoch. 



A third fact which came out was, that these old terraces vary in height just 

 as the present banks of the stream vary at different parts of the river course, and 

 in something like the same proportions. Usually the present banks and haughs 

 of the Earn are 5 to 6 feet above the stream, but in some places we find them only 

 3, and in other cases they rise to about 10, as near the Bridge of Strowan. 

 The difference is due to the form of the valley, and still more, I believe, 

 to the force of the current. Now, there is precisely the same kind of 

 variation in the levels of the old terraces. As the present banks and haughs 

 may be anything from 3 to 10 feet, so the second terrace varies from 16 

 to 24, and the highest from 35 to 60. The cases where extremes occur 

 are rare ; but this general truth must be recognised, that as the present banks 

 vary in height with the locality, so do the ancient terraces. 



Connected with this, however, there is one further circumstance which 

 deserves to be noted ; the height of the old terraces varies with the incline of the 

 river bed. Where the incline is greatest, there, of course, the current ran 

 strongest, and there the terraces are highest. When the gradient is low, the 

 terraces get low. It is difficult, indeed, to bring out the exact truth on this 

 point, for it is necessary to make allowance for the varying width of the valley ; 

 but in comparing the different parts of the river, there is seen to be a distinct 

 proportion between the steepness of the incline and the height of the deposits. 

 Thus, from the foot of Glenartney to Kinkell, the distance in a straight line is 

 about ten miles, and there the descent of the river is nearly 200 feet. From 

 Kinkell to Bridge of Earn is more than eleven miles, and there the descent is 

 about fifty feet. Now, it is along all the upper section, where the current ran 

 strong, that the terraces rise high ; and along all the lower portion, where the 

 current ran slow, the terraces subside. Precisely the same thing is seen on the 

 Teith. Above Doune the descent is rapid, and the current strong. Below 

 Doune all is flat, and the current gets slow, and it is in the upper portion that 

 the terraces are raised high, while below Doune their height markedly diminishes. 



VOL. XXVI. PART I. 2 X 



