152 



REV. THOMAS BROWN ON THE OLD RIVER TERRACES 



valley there appeared three terraces, as represented in sketch 2.* Along the 

 river side is the lowest terrace, a, about six feet above the water, being the 

 height of the present banks. Further back, and rising above it, is the second 

 terrace, b, about sixteen feet higher than the first, or twenty-two feet above 

 the water ; and still further back is the third, running along the sides of 

 the valley, its level being, at the point where I measured it, about 57 feet above 

 the bed of the stream. In this last the line of escarpment has been somewhat 

 broken by denudation, but the continuity of the terrace itself is obvious at a 

 glance. The whole of these levels consist of gravels and sands with clay in 



Sketch 2. — Near the Foot of Glenartaey. 



different proportions. Near the point c, the highest terrace was well laid open, 

 and showed the following structure, beginning at the surface : — 



1. Gravel with clay, the pebbles lying on their flat sides, 



2. Pan, . 



3. Gravel, sandy above, coarser beneath, 



4. Fine brown sand, in layers, . 



5. Fine gravel with sand, 



Feet. 

 2 



Inches. 

 





 2 

 



1 

 3 



8 



depth 



unknown. 



This was evidently the work of running water, and the question again arose 

 whether it had not been deposited by the river at some period when its floods 

 ran much higher than at present, and whether that threefold system of 

 terraces might not be found to throw light on the whole of these old river 

 deposits. On going across to the Turrit, where it comes out from the hills 



* For this series of sketches I am indebted to a young friend, Mr W. B. Murray, an art-student 

 of our Edinburgh School, who has been very successful in his rendering of the scenes. Along the 

 Earn it has, in three or four cases, been necessary to suppose the woods thinned, in order to show 

 the real form of the ground, but this has been done as sparingly as possible. On the Teith there was 

 less need for this except in Sketch 12, and even on the Earn all the finest examples of the terraces, 

 such as those in Sketches 6 and 7, are given exactly as they appear in nature. 



