ARGYLL INVERARY DISTRICT. 361 



I venture to lay before the Society some observations upon the 

 pheenomena of a certain district in Argyllshire, vpith vrhich, from 

 residence, I am particularly acquainted, in the hope that they may 

 possibly suggest some idea of the conditions or forces vphich seem to 

 have determined the position, arrangement, and mineral character of 

 the metamorphic strata as there developed. 



The first feature in the general structure of the country, vphich is, 

 I think, well vi'orthy of notice, is one vrhich belongs not only to the 

 district I have just referred to, but, so far as I have been able to ob- 

 serve, to the v\fhole county. It is the great spaces over which one 

 uniform line of dip is preserved by the strata of the mica-slate ; a dip 

 which has no reference to any apparent intrusive rocks, but which, 

 on the contrary, only changes where these rocks effect the alteration. 

 The general strike-direction of the Argyllshire strata is that which 

 is so prominently marked on the Map of Scotland by its deeply in- 

 dented western coast, viz. from N.E. to S.W. ; whilst the dip in 

 one system of valleys is N.W., and in another S.E. Thus, on the 

 Argyllshire shore of the basin of the Clyde, the mica-slates dip 

 towards the S.E., this dip being exactly reversed on both sides of 

 the great valley occupied by the waters of Loch Fyne. The block 

 of intervening land in which this change takes place is happily inter- 

 sected by a cross glen, which presents a magnificent section of the 

 anticlinal ridge ; ably and accurately described by Sir Roderick Impey 

 Murchison in his paper communicated to the Society*. 



This anticlinal has no aspect of being caused by any central mass 

 of granite throwing off the strata in opposite directions. I do not 

 merely mean that no such central mass makes itself visible, but that 

 the regularity of the reverse dips, and the great extent longitudinally 

 over which they are preserved, do not suggest any notion of a local 

 upheaving action. 



I now come to the special subject of this paper, — the structure 

 of the next dividing block of land between two great valleys, viz: 

 between Loch Fyne on the one side and Loch Awe upon the other ; 

 embracing what I have called the granitic district of Inverary. I am 

 best acquainted with it, of course, in the immediate neighbourhood of 

 Inverary, but sufficiently so throughout its entire length of some 

 twelve or fifteen miles to feel pretty sure of the essential uniformity 

 of its structure throughout. 



I have already mentioned that the strata on both sides of Loch 

 Fyne preserve the same north-western dip which they first assume half- 

 way between the Clyde and Loch Fyne. This fact will at once be 

 observed by the geologist who ascends that arm of the sea, and will 

 account to him for some peculiar features in its scenery. Its bed 

 being in the hollow between strata which dip at a high angle, but are 

 conformable with each other and with the line of the Loch, one 

 bank, of course, presents the escarpment, and the other the sloping 

 side. Accordingly, along the upper reach of Loch Fyne, the right 

 or more southern bank presents a steep but smooth and somewhat 

 unbroken ridge, whilst the more northern bank has a much more 

 * Quart. Jovirn. Geol. Soc. vol. vii. pp. 168, 169. 



