part 2] THE SOrTH-WEST HI&HLAlvrDS or SCOTLAND. 119 



r Thick grey pelitic schist — Leven Schists. 

 Ballachiilish Nappes Thin, fairly persistent limestone — remnant of 



I Ballachulish Limestone. 

 Ballachulish Thrust. 

 Banded pelitic schists and quartzite — remnant of 



Leven Schists. 

 Quartzite, locally very thick — Glen-Coe Quartzite. 

 Gneissose flagstones — Eilde Flags. 



Of these rocks, eveiything below the interbedded pelitic schists 

 and pebbly quartzite is referable to the Ballappel Foundation. 

 The remainder is obviously the interrupted continuation of the 

 similar association cropping out west of the Etive Grranite, and 

 alread}^ correlated (p. 118) with some portion of the Islay Quartzite, 

 Transition Group, and Easdale Slates. The agreement will 

 perhaps be better appreciated after reading the following detailed 

 description : — 



Near the south-east of the granite, one passes north-eastwards from the 

 Ardrishaig-Phyllite outcrop on to a belt of black slate-hornfels about 

 700 yards wide. Graphitic layers and streaks are abundant, and rusty 

 weathering due to pyrites is characteristic. At the same time quartzose 

 material is well represented, locally giving rise to a band of quartzite. 



Beyond the black slate, one encounters an equal breadth of quartzite, 

 which, though somewhat impure, is everywhere markedly pebbly, and but 

 little split by partings. Beyond this main quartzite, one meets with grey pelitic 

 hornfels in which for 800 yards bands of pebbly quartzite continue as a minor 

 feature. 



The black slate mentioned above as succeeding the Ardrishaig 

 Phyllites is not so pi'ominent in this section as it is west of the 

 Etive Grranite, but this defect is made up in the Dalmally exposures 

 east of the Glen-Strae Fault, Avhere a very big development of 

 black schist with subordinate limestone occurs. Mr. J. B. Hill has 

 rightly emphasized the manner in which these black schists are 

 for the greater part interposed between the Ardrishaig Phyllites 

 on the south, and the pebbly quartzite on the north (1908 h, 

 p. 28), although the latter has its outcrop broken to some 

 extent b}^ bands of black schist. Various conclusions follow from 

 the evidence adduced in the present and preceding sections : — 



(1) A pebbly- quartzite and black- slate assemblage has been traced north- 

 eastwards from the Islay Archipelago to Loch Creran and thence eastwards 

 to Dalmally and the Ben-Doirean Range. ^ This, with the grey pelitic group 

 carrying the interbedded pebbly quartzite, will be termed for brevity the 

 Islay-Easdale Assemblage; its outcrop is clearly shown in PI. I, 



(2) On the inside of the curved outcrop of the Islay-Easdale Assemblage 

 lie the Ardrishaig Phyllites of the Loch-Awe Nappe ; on the outside, a varied 

 succession depending on locality. 



(3) There is abundant evidence that the Islay-Easdale Assemblage underlies 

 the Loch- Awe Nappe and overlies the rock-groups appearing along its outer 

 margin. This evidence may be considered under the headings 3 a-3 c.^ 



^ See also 1922, Report A, par. 8. 



■^ Ihid. compare (3 a) & (3 c) with Report A, par. 4. 



