280 me. e. b. bailey on the [June 1913.,. 



15. The Loch Awe Syncline (Argyllshire). By Edward 

 Battersby Bailey, B.A., F.G.S. (Bead February 26th.. 

 1913.) 



[Plates XXXI & XXXII.] 



Contents. 



Page 



I. Introduction 280 



II. The Volcanic Bocks 282 



III. Epidiorite-Fragments in Conglomerates near 



Loch Awe 287 



IV. The Stratigraphy 289 



V. The Structure and the Metamorphism 296 



VI. Bibliography 298 



VII. Appendix on the Stratigraphy 299 



I. Introduction. 



The district described in the present paper forms portion of the low- 

 coastal region of Argyllshire, and presents few physical difficulties 

 to the investigator. There are, however, other difficulties, resulting 

 from the fact that igneous and sedimentary schists occur together 

 here in about equal proportions, and have been alike subjected to a 

 system of small-scale isoclinal folding ; moreover, though lavas are 

 well represented, fully half the igneous schists are sills, and so 

 are of little use for stratigraphical purposes. 



Under the circumstances, it is not surprising that progress has 

 been slow. Macculloch, writing in 1819 [1, p. 292], 1 did himself 

 less than justice, for he seems to have decided against the 

 igneous origin of any of the schists of the region, erecting his 

 Chloritic Formation to include the whole assemblage. In regard 

 to structural matters he was more fortunate, for he gave a clear 

 account of the lie of the rocks in the southern part of the district, 

 where he located 



' a line of vertical beds . . . towards which the strata converge on each side, 

 both from the south-eastern and north-western boundaries ' 



[1, pp. 288-89]. In nature, of course, the line is rather vague, 

 being more correctly designated as a narrow belt, where both 

 bedding and cleavage are often extremely steep or vertical. This 

 belt runs from the eastern shores of Loch Sween, north-north- 

 eastwards through the southern end of Loch Awe. For some 

 miles to the south-east of its course the prevalent dip of both 

 bedding and cleavage is towards the north-west, and vice versa. 

 There is also a tendency for the angles of inclination to be higher 

 near the central belt than at a distance ; but this does not preclude 

 the existence of many open anticlines and synclines, affecting 

 bedding, not cleavage, quite close up to the central line. 



1 The numerals in brackets refer to the Bibliography, § VI, p. 298. 



