Vol. 60.] MOINE GNEISSES OF THE EAST-CENTRAL HIGHLANDS. 423 



(e) The Succession in the Braemar Area. 



The Sequence. — One of the most striking features of the 

 scenery of the East-Central Highlands is the great chain of quartzite- 

 mountains that stretches from Beinn y Ghlo, near Blair Atholl, to 

 Mor Shron, close to Braemar. Parallel to this are minor chains, 

 composed of the same material. While the quartzite is intensely 

 hard, and resists denudation, the rocks associated with it, and 

 in particular a bed of limestone, are much softer, and yield readily 

 to erosion. These beds, in consequence, have weathered away to a 

 great depth, and hence much of the district is characterized by an 

 alternation of high ridges and deep valleys; the trend of* which is 

 determined by the strike of the outcrops of the Quartzite. It is 

 with the composition and order of succession of the rocks forming 

 this special type of scenery that we have now to deal. The locality 

 selected for the purpose lies 2 miles south of Braemar ; but other 

 parts of the district will be referred to. for the purpose of aiding the 

 investigation . 



The succession in this group of rocks, in this area, whether 

 ascending or descending, is as follows : — 



1. The Central-Highland Quartzite. 



2. The Parallel-Banded Series: Honest ones. etc. (passing into Moine 



Gneisses). 



3. The Little Limestone. 



4. The Dark or Leaden Schist. 



5. The Main Limestone. 



6. The altered, parallel-banded Calcareous Shales (Calc-Flintas). 



1. The Central-Highland Quartzite. — The Quartzite was 

 originally a bed of sandstone, more felspathic in some parts than 

 others, that has been intensely folded on itself, so as to build up 

 enormous masses of higbly-quartzose rock. It is conveniently 

 called a ' quartzite,' because, however much recrystallized, it almost 

 always retains the angular weathering of an ordinary quartzite. 

 Often there is no sign of the mechanical deformation usually met 

 with in the other members of the series ; and it is clear that it was 

 altered to a quartzite, not only before the crystallization of the 

 Highland rocks took place, but prior to their crushing. Over almost 



Note on the Map, fig. 4, p.4%2. — In this map the sequence is built up. Here, 

 again, the stream and scar-sections are mostly clear, but the flatter ground is 

 greatly obscured by thin peat and Drift ; owing to the intense folding, there is 

 often no sharp junction between the different rock-groups. Starting from the 

 margin of the Quartzite, we sometimes see, first the edge of the Quartzite 

 repeatedly folded with the Passage-Beds, then the Passage-Beds folded with the 

 Little Limestone and Dark Schist, and, finally, the Dark Schist only. There 

 is, however, in many cases, a fairly-sharp junction with the Quartzite. The 

 line separating the Passage-rocks from the Dark Schist often implies simply 

 that one rock is the dominant component on one side of the boundary, the 

 other rock on the other. The outcrop of the Little Limestone is so narrow as 

 to be often untraceable. The quartz-porphyry outcrop, shown west and north- 

 west of JNewbiggin, also extends to the east of the burn, immediately north of 

 the Main Limestone. 



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