in the Middle liegion of Scotland. 177 



of the rock (a felspatliic claystone), dips at 40° ; the strife are 

 horizontal, parallel, and quite straight, and extend over a 

 surface from 1 to 3 feet in breadth (vertically), and about 25 

 feet in length. Their direction corresponds w^ith that of the 

 valley at the place, being precisely ENE. and WSW. The 

 valley is about 300 feet in depth, and, including the upper 

 portion, which curves round the west end of Torduff Hill, 

 about three quarters of a mile in length. It is such a valley 

 as might give birth to a glacier at a glacial epoch. On the 

 top of the same hill, about 900 feet above the sea, striae and 

 grooves, in short lines, can be detected at intervals, pointing 

 also very uniformly ENE. and WSW. A floating body, 

 such as ice, coming hither from the west, would have a course 

 pei'fectly unobstructed for 20 miles ; for the high ground in a 

 WSW. direction presents the aspect of a plain. Such a body, 

 as it passed along, would graze the western front, the top, 

 and the flanks of this hill ; and accordingly we find that, like 

 the hills in the low country, it has the crag-and-tail form, 

 with the crag to the west. Both the head and foot of the 

 hill exhibit proofs of abrasion and grooving, but whether by 

 glacier ice, or floating ice, or both, is still a problem. 



27. At Fenton Tower, direction ESE. and WSW., noticed 

 by Sir James Hall. 



28, 29. At Old Markle and Gosford Spittle, on the North 

 British Railway, the groovings horizontal, and very distinct, 

 but the surfaces are vertical, they seem to me to give no sure 

 indication of the line of motion. 



My principal object in this paper was to register the phe- 

 nomena observed ; and, in speaking of their probable causes, 

 I shall endeavour to be brief. 



The Grampian District. — We have seen that, on the east 

 side of this district, at Loch Tay, the abrading and grooving 

 agents moved eastward ; that on the west side, at Glen Spean, 

 Loch Leven, and Loch Etive, they moved westward ; and 

 that on the south side, at Loch Fine, Loch Eck, Loch Long, 

 and Gareloch, they moved southward. It follows that 

 the nucleus of this physical force, the common centre from 

 which the agents moved, was in the group of mountains ex- 

 tending from Loch Goil northward to Loch Laggan, dividing the 



VOL. XLVII. NO. XCIII. — .JUJiY 1849. M 



