46 Proceedings of the Royal Physical Society. 



Scottish Central Eailway runs marks the line of retreating 

 glaciers into central Perthshire, no less do the series of barren 

 moorland plateaux which stretch in terraces from our coign 

 of observation to the Grampians. The series of small shallow 

 lochs, of which the six at the Stormonth district are the ter- 

 mination, may be the memorials of successive torrents. This 

 appears probable, rather than that they are dammed up 

 channels of the Tay, from other mountain lochs of apparently 

 the same set, being at altitudes of 1000 feet or more. The 

 soil round Blairgowrie is a light gravel, much akin to the 

 underlying conglomerate rock, more adapted for arboriculture 

 than for modern husbandry — very sterile, indeed, in this 

 respect, except for the special strawberry crops, to which 

 much of it is now devoted. The same characteristics apply 

 to the ground flanking the high conglomerate escarpment 

 bounding the north-west side of the valley. It is the pro- 

 duct, indeed, of these mountain torrent streams — the Ericht, 

 the Alyth, and the Isla. When joined into the latter in the 

 centre of Strathmore, the current has lost boulder-carrying 

 power, and only spreads sand and clay, hence the high 

 agriculture round Cupar- Angus. The manner in which the 

 Ericht now rapidly cuts out its conglomerate bed may be 

 studied in its channel immediately above Blairgowrie. 



The Lornty joins the Ericht about half a mile out from 

 Blairgowrie, after a course of about the same length, and 

 presents many of the peculiar aspects of a mountain stream 

 in miniature. On either of its shelving sides, which owe 

 much of their peculiar physiography to the series of trap 

 dykes running east and west through this district, and which 

 also greatly aid in shaping both the western mural escarp- 

 ment of Strathmore, as well as the Sidlaws, on the opposite 

 side of the valley, are marks of combs, caused by sudden 

 transverse currents, only active in very stormy seasons. The 

 side valley on which stands the old ruins of Glascune Castle 

 is a very marked example of a comb on a constant feeder ; 

 and at its junction with the Lornty will be found a long 

 gravel funnel. Nearly opposite, at the head of a grass park, 

 the surface soil has slipped down nearly a foot and a half 

 from a dry-stone dyke. The inclinature of a field is such 



