The Geology of Lochrutton. 17 



4. An interesting exposure in the channel of the Lade 

 opposite the cottage of Old Mill shows the old rock surface 

 dipping underneath the boulder clay of the Moat. The dip 

 shelf upon which the Lade is resting affords in itself sufficient 

 evidence to prove a rapid descent in the old contour. 



5. A prominent band of rock stretches across the foot 

 of the Loch and through the village, giving a conspicuous 

 exposure on the road. When sinking a well at the School- 

 house, a few yards south of this outcrop, the rock surface 

 was found to be 15 feet lower, which gives a very rapid dip 

 into the valley. 



6. In 1850 the old chart gave the greatest depth, 52 ft. 

 6 in., at a point in the Loch between Button's Cairn and the 

 western bank. 



Pre-Glacial Valley. 



It is remarkable that the direction of the old river 

 channel agrees with the general trend of the valley system 

 of these uplands. Evidently the direction of the strike has 

 been a leading factor in determinating the course of the 

 streams. The irregularity of the anticlinal folds would, 

 however, occasion sharp departures from the normal course. 

 In the upper valley (Merkland) the direction was easterly, 

 agreeing with the strike obtaining in that locality; about 

 Auchenfranco the valley swung a little to the left, and tin- 

 Rutton river tlowed due north, and was discharged into the 

 lower and larger Bogrie valley. The upper Merkland and 

 the lower Bogrie agree with the direction of the strike. The 

 middle portion now occupied by the Loch and the Moat was 

 a transverse valley, like the Urr valley further west. A 

 striking similarity is to be found in the Cairn and its tribu- 

 taries, the Auld \Vater and Glen Burn. The Glen Burn flow s 

 north-west along the line of strike until it enters the Auld 

 Water, which runs at right angles in a transverse direction. 

 At the village of Shawhead the Auld Water turns at right 

 angles to the left, and flows along the strike through the 

 Dalquhairn gorge into the Cairn. The transverse (south- 

 east) direction is then resumed for several miles by the valk'v 

 of lower Cairn. 



