446 MR. G. BARROW ON THE MOINE GNEISSES [Nov. 1 904, 



greatly folded. Numerous infolds of Dark Schist occur in this, but they 

 cannot be traced on the ground. A belt of ground to the south-east of the 

 main mass of the Moine Gneisses, within which the passage from Moine Gneiss 

 to Honestone occurs, is left blank. The limit of the main mass of the Moine 

 Gneisses is obtained by joining up the westernmost outcrops of the Main 

 Limestone, which occur as small infolds. The area is typical of the whole 

 district ; while the stream-sections are unusually clear, the flanks of the valley 

 are greatly obscured by downwash and patches of Drift, and the boundaries 

 between the different outcrops are often uncertain. 



Plate XXXIV. 



[For the inicro photographs from which this and the following three plates are 

 reproduced, I am greatly indebted to Mr. Hall, of the Geological Survey.] 



Fig. 1 (88). First cutting above Struan Railway-station, Garry area. Moine 

 Gneiss with typical granulite-structure. (See p. 406.) 

 2 (86). Bed of the Garry below Dalnacardoch Lodge. Much microcline ; 

 also showing quartz-bleb structure. (See p. 408.) 



Plate XXXV. 



Fig. 1 (99). Gaick Forest. Inverness. Epidotic gneiss. (See p. 410.) 



2 (107). Cairn Fidhleir. Tarf Area. The round- weathering oligoclase- 

 gneiss. (See p. 411.) 



Plate XXXVI. 



Fig. 1 (84). Bed of the Garry, opposite Dalnacardoch Lodge. Abundant 

 microcline, containing minute quartz-blebs. Green mica and a 

 little plagioclase. (See p. 408.) 

 2 (136). The Passage-Rocks at Auchallater, Glen Clunie, Braemar. Show- 

 ing the fine biotite-granulite, always present in the Honestones 

 or Passage-Rocks, and often their dominant constituent. (See 

 p. 424. 



Plate XXXVII. 



Fig. 1 (113). Just above the road on the west side of Braemar. Highly- 

 quartzose Moine Gneiss, with lines of heavy minerals (see p. 424). 

 This is part, probably, of the Quartzite in a ' Moine-phase.' But 

 it is difficult to say, at this locality, where one rock begins and 

 the other ends : they were obviously all part of the same bed 

 originally. 

 2 (150) Sron-Dias Crags, upper part of Glen Firnate, south-east of Beiun 

 y Ghlo. An illustration of a slight reversion to conditions of 

 deposition similar to those south-east of the main area of the 

 Moine Gneiss, the rock on the margin of the Quartzite having 

 the composition and structure of a fine Moine Gneiss. (See 

 p. 440.) 



Discussion. 



Dr. Horne said that he was glad to have the opportunity of 

 taking part in the discussion, because he had recently visited the 

 sections between Blair Atholl and Braemar under the guidance of 

 the Author, and had the privilege of reading his manuscript now 

 submitted to the Society. He wished to express his high appre- 

 ciation of the detailed mapping done by the Author, and of his 

 prolonged study of the petrographical characters of the rocks of 

 that region. 



