158 



REV. THOMAS BROWN" ON THE OLD RIVER TERRACES 



over the grounds of Ochtertyre ; and when one finds these deposits in the 

 same position above the ravine and below it, it seems vain to ascribe them to 

 some lake formed by the barrage of the river. 



Tracing the course of the Earn from Crieff to Dalpatrick, we again reach a 

 point above the old castle of Innerpeffray where the channel is narrowed between 

 high grounds. Standing near Easter Dalpatrick and looking upwards, we have the 

 scene as represented in sketch 6. The present banks and meadows, a, are sur- 

 mounted by the second terrace b, and that by the higher level c, all in full 

 preservation.* Again, the idea might be suggested of a bar above Innerpefiray 

 forming a lake, but again the explanation is forbidden by the continuous course 

 of the deposits, and more especially by their appearance when the narrow 

 portion of the river has been passed, and the banks again spread out into a 

 wide open valley. This takes place immediately below Kinkell, where the 

 threefold terrace system is very remarkable, as shown in sketch 7. 



wf?c 





Sketch 7. — Kinkell Bridge, looking up. 



A section of terrace c, on the eastern side of the Machany, is laid open by 

 the cutting of the road, and is given in PL IV., fig. 1. The details are — 



a, Humus. 



b, Carse clay, grey, unlaminated tenacious. 



c, Laminated clay with partings of sand. Laminse a half inch in thickness. 



The series of deposits at this point are specially important, because there is no 

 position further down the valley where it is possible to suppose that a barrier 

 could have ever been thrown across. These are not lake margins. 



The lower portions of the river, as it passes Dunning, Forteviot, &c, were 

 examined somewhat more rapidly. The threefold system of terraces seems to 

 have been less distinctly preserved. A point, however, is given in sketch 8, 



* Immediately beyond the farm-house the railway gains the summit of terrace c, and the view 

 shown in sketch 1 is seen looking up the valley. 



