74 Mr. Lyell on a recent Formation of 



tally; the newer members of the same series dip away from the axis on either 

 side, with an inclination constantly increasing as they recede from it*. 



The eastern part of the great valley of Stratl^more is composed entirely of 

 old red sandstone. The strata are disposed in a trough^ those on the north- 

 ern side of the anticlinal line of the trough dipping rapidly to the south, and 

 occupying, consequently, a narrower space than the corresponding strata on 

 the southern side, which dip more gradually in an opposite direction. The 

 lowest stratum of the sandstone is a conglomerate, the outcrop of which forms 

 a range of low hills on either side of Strathmore ; one range, to which the 

 Alyth hills belong, flanking the Grampians ; the other, which comprehends 

 the hills of Finhaven, flanking the Sidlaw. Above the conglomerate is a 

 series of red-sandstone strata, which yield an excellent freestone ; and above 

 these are some very argillaceous beds, of a deep ferruginous-red colour, pro- 

 vincially termed "calm." 



These two last divisions of the old red-sandstone, which generally occupy 

 the centre of Strathmore, are often buried beneath vast deposits of gravel, the 

 debris of the various primitive rocks which compose the Grampians, and of 

 the sandstone strata on which the gravel immediately reposes. This debris is 

 of ancient date, and by Professor Buckland would be called "diluvium," a 

 term by which I shall speak of it in the sequel. 



One of the most considerable of these accumulations is in the vicinity of 

 the Bakie Loch. Its southern boundary is the river Dean, and its northern 

 the road leading from the bridge of Ruthven to Lindertis, and onwards in 

 the direction of Kirriemuir. This diluvial district derives a singular character 

 from the confused manner in which the debris is heaped up. The eye is 

 struck with the absence of that regular system of valleys which it is accus- 

 tomed to trace in hilly tracts. Large hillocks are seen of sand and gravel, 

 irregularly scattered on all sides, and swampy hollows between these hillocks, 

 from which the waters have no natural drainage. Some of these hollows are 

 filled by peat; others are occupied by lakes, among which is the Bakie Loch. 

 This loch is situated in the parish of Ayrly, about 9 miles due west of For- 

 far, about 4 miles north-east of Meigle, and about the same distance north- 

 west of Glammis. A castle of the same name, of which the foundations only 

 now remain, formerly stood on the western bank. The loch once extended 



* The strata dip with great regularity to the south-east along the coast from Dundee to the 

 Red Head ; but Mr. Blackadder has long remarked (and I have had opportunities of confirming 

 the fact), that the inclination is to the south-west on proceeding further westwards. This change 

 takes place suddenly to the west of the meridian of Dundee. 



