330 Reports and Proceedings — Geological Society of London. 



above. A section along the North Esk Eiver is described in detail, 

 and other sections referred to it. The lower division consists of 

 fine-grained sandstones (bearing microcline), grey slaty shales, 

 jaspers (sometimes containing circular bodies resembling radiolaria), 

 and a variable series of basic igneous rocks (' green rock ') of coarse 

 texture and probably intrusive origin. The upper division consists 

 of conglomerates, pebbly grits, dark and v^hite shales, pebbly 

 limestone, and grey shale. The age of the series cannot be definitely 

 ascertained, but the low^er division is compared with the Arenig 

 cherts, etc., of the Southern Uplands, while the Margie Series is- 

 newer than this, but older than the Old Eed Sandstone, Both 

 groups have been much deformed, but the sediments contain clastic 

 micas and have undergone practically no recrystallization, and the 

 igneous rocks are never changed into hornblende-schists. The 

 deformation is greatest near the junction with the Highland Schists, 

 giving rise to a deceptive appearance of an upward succession and 

 an apparent transition in crystalline character, but the crushing, 

 never extends more than a few yards into the Highland Series. 

 A major thrust separates the Highland Schists from the Jasper and 

 Green Eock Series, and a minor thrust generally separates the 

 latter from the Margie Series. The position of the major thrust 

 and that of the later great boundary fault skirting the Old Eed 

 Sandstone have been determined by the outer limit of the aureole- 

 of crystallization of which the South-Eastern Highlands form a part. 

 The harder crystalline schists to the north-west have snapped off 

 from the softer portions, now covered by newer rocks to the 

 south-east. 



3. " On the Crush-Conglomerates of Argyllshire." By J. B. Hill^ 

 Esq., E.N. (Communicated by E. S. Herries, Esq., M.A., Sec.G.S., 

 with the permission of the Director of H.M. Geological Survey.) 



While the sedimentary origin of the Highland Boulder-bed is 

 proved by the foreign boulders contained in it, there occur in the 

 Loch Awe region certain conglomerates, often along definite horizons, 

 which may have been confused with it, but which the author is 

 able to prove have originated by crushing. The sedimentary rocks 

 of the area include all the members of the Loch Awe Series, consisting 

 of grits, slates, and limestones, the latter being mostly gritty in 

 character. Associated with these is an enormous amount of igneous 

 material of Dalradian age, ranging from intermediate to basic in 

 composition, together with porphyrite-dykes probably of Old Eed 

 Sandstone age and a plexus of Tertiary dykes. The sediments are 

 everywhere folded, the folds being of isoclinal type. The Dalradian 

 igneous material consists of epidiorites ; and evidence is brought 

 forward to prove that these rocks are intrusive, while their great 

 apparent bulk is probably to be accounted for by repetition due to- 

 folding. A petrographical description is given of the various types- 

 of rocks represented among the epidiorites, the minerals of which 

 include hornblende and felspar, with chlorite, epidote, calcite, quartz, 

 and iron-ores. There is every gradation in texture from a coarse- 



