The Geologv of Lochrutton. 21 



two were united — forming one sheet, with the MerklancI 

 drumlin as an island. Such a large mass of water would 

 rapidly remove, by means of an outlet, any surface debris 

 at the lower end. In this way the water level would fall, 

 giving again an upper and a lower loch. 



Outlets. 



The duration, or rather the very existence, of ii 

 morainic loch depends primarily upon the point of emergence 

 of its outlet. This occurs sometimes at the weakest point — 

 that is, close to the buried channel — or it may happen at any 

 other point which is lower. Lake Windermere is a typical 

 example of escape by the lowest point. Its outlet, the River 

 Leven, is considerably removed from the buried channel at 

 the foot of the valley. The weakest point of the Merkland 

 barrier — that is, the material that would be easiest removed 

 by stream erosion — would be at the drumlin. The lowest 

 point was situated behind the INIerklandwell cottage ; and 

 along this depression the outlet sought its way. .'\t the foot 

 of the Rutton Loch the lowest point was found to be on the 

 opposite side of the valley. The trend of the glacial flow 

 explains this. The Lade found the lowest point to be in 

 the angle formed by the eastern side of the buried valley and 

 the rounded ends of the Moat drums. 



Recent Modificatioxs. 



Any change that has since occurred in the lochs has 

 been along two distinct lines : — (i) Excavation by stream 

 erosion; (2) formation of alluvial flats by sedimentation. 



Although these two forces are in direct opposition tO' 

 each other, yet there is such an intimate and continued 

 relation between the two at every step that we must consider 

 the present condition of things as the result of one process 

 — modification. 



Merkland Loch. 



The path chosen by the Merkland Burn to convey the 

 surplus water of that Loch traverses at least two bands of 

 hard rock. The band in front of the cottage is 50 feet wide. 



