608 D. MILNE HOME ON THE PARALLEL ROADS OF LOCHABER. 
The top of the barrier I found to be about 90 feet above the level of the river; 
and 135 feet above the sea. The bank of sand is about 35 feet deep and 100 
yards wide, the depth of the erosion of the rocks is 50 feet. 



























: Xt e "UML |, > 
\\\' a mI . 
H O87 
>> HHEs Le 

Fig. 5. (See p. 607.) 
Ground Plan of detrital bank near the mouth of the River Gussern, 
crossing the valley. SS represent the two portions of the bank 
still remaining, and united to the hills on each side. 
Glen Spean Valley represents several examples of the same kind. Near the 
falls of Monessie, detritus had originally filled the valley to such a height as to 
form a lake, the surface of which reached a height of 520 feet above the sea. 
The beach line of this lake is distinctly traceable from Auchenleurich Post 









Fig. 6. (See p. 607.) 
Section of detrital bank in valley of Gussern, showing how the river 
has cut through it, and the subjacent rocks. 
Office and Monessie at its lower or West end, to Inverlair Falls at its upper or 
East end, a distance of about 3 miles. Figures 7 and 8 are intended to shew 
how the lake was drained. At Monessie, the channel of the river is about 100 
feet below the level of the old beach line. A great mass of detritus still crosses 
the valley here for about two-thirds of its breadth. The river issuing from the 
lake, cut through the detritus, and drained the lake. 
From the foregoing statements, two points seem established —(1.) That all 

