282 Mr Maclaren's Remarks on Natural Terraces 



mm, the level haugh or holme which skirts the river, rising 

 from 6 to 15 feet above it. - 



The breadth of the valley measured right across, at the 

 level of these terraces, that is, from h to k, may be about a~ 

 mile. 



The position and materials of the two terraces and the hill 



b, leave scarcely any doubt that they are remnants of a vast 

 bed of sand and gravel which filled the valley from side to 

 side, and was deposited at an ancient period by the sea, when 

 it stood much higher than at present, covering the plain of 

 Perthshire up to the Grampians, and occupying the valley of 

 the Tay far above Dunkeld, in the shape of a narrow firth like 

 Loch Etive or Loch Long. 



I am indebted to a scientific friend for authentic data which 

 enable me to fix the difference of level between the Tay at 

 Perth and the Tay at Dunkeld in round numbers at 160 feet. 

 Adding 120 for the height of the terraces, and 20 more for 

 the probable elevation of the water above their surface, it fol- 

 lows that the relative level of the sea must have been 300 feet 

 higher when these terraces were formed, than it is at this day. 



There is a small conical hill within the Duke of AthoU's 

 park, very near the village, which, if not artificial, must be 

 another remnant of the plateau of gravel and sand. 



The terraces are not confined to the vicinity of Dunkeld. 

 The road to Taymouth runs along the south side of the river 

 as far as Logierait, and the traveller finds on his left hand, 

 not one or two, but a series of remnants of terraces, like a and 



c. They are all of sand and washed gravel ; the sand occa- 

 sionally unmixed, very pure, and stratified. At many parts 

 they project from the hill side into the low haugh land, like 

 promontories or peninsulas running into the sea. Their front 

 and sides are in general sharply cut, and steep, indeed, as 

 highly inclined as the nature of the material will admit. A 

 portion extending half a mile along the valley may sometimes 

 be seen, but usually they are much shorter. Their height 

 varies much ; and this is what might be expected ; for the 

 stream or receding ocean, in cutting away all the middle, and 

 hollowing out deep cavities in the sides, must have reduced 

 the height of many of those parts which escaped destruction* 



