12 The Geology of Lochrutton. 



The present watersheds have undergone a persistent 

 progression in the course of several geological ages, and 

 consequently many of the lochs are of quite recent origin 

 and rivers are now running in directions altogether different 

 from that of their original courses. Any addition to our 

 knowledge of the pre-glacial river system of South Scotland 

 will be of considerable value — commercially and economically 

 — to the district embraced. 



In this paper, however, we are concerned only with that 

 district occupied by Lochrutton and its drainage area. A 

 comprehensive view of the history of the physiographical 

 conditions of this region from the Pliocene Age to the present 

 day will give a clearer conception of the changes involved 

 in the formation of the Loch, and a true appreciation of the 

 natural forces at work accumulating and excavating. This 

 will considerably simplify the problem of obtaining a per- 

 manent supply of pure water from this natural reservoir for 

 the needs of Dumfries and Maxwelltown. Unfortunately, 

 there has been no detailed geological investigation of the 

 district. The Memoir of the Geological Survey (published 

 1877) simply states that this Loch rests partly on rock and 

 partly on glacial drift. 



Physical Features. 



The Loch, which is at present about 139 acres in extent, 

 is situated in a large hollow running approximately north 

 and south. On the eastern side the Hill's Hill, Barlae, and 

 other heights form a long ridge rising 300 feet higher than 

 the Loch. This high ground acts as a leading watershed. 

 The streams on the eastern slopes drain either into the Nith 

 or into the Urr below Dalbeattie. West of Lochrutton, the 

 Barnbachle Hill, at an altitude of 604 feet, acts as the water- 

 shedding area between it and the Milton. To the north of 

 the Loch the valley gradually opens out, and is merged into 

 a larger valley drained by the Bogrie Burn, and trending 

 east and west. At the southern or upper end of the Loch 

 there is, first of all, an old moss (Merkland), hemmed in by 

 steep sides, and after that the remnant of a V-shaped 

 valley extending in a westerly direction to the valley head 



