﻿1851.] MURCHISON — SILURIAN ROCKS OF SCOTLAND. 



1G9 



and to which I gave the name of Argyll's Bowling Green, from the 

 well-known rugged mountains which occupy a portion of the central 

 or axial mass. The section best exposed is that which is seen in 

 passing from the Clyde, near Kilmun, to Strachur on Loch Fyne ; 

 the chief features of the central elevation and disturbance being 

 admirably laid open on the shores of Loch Eck. This axial eleva- 

 tion explains, in my opinion, how various regularly stratified rocks 

 (such stratification being obviously quite distinct from crystalline 

 cleavage) have been rolled over and over in the Highlands, so as 

 to form a series of broad and gnarled ridges and deep troughs, the 

 major axes of both of which are parallel to the strike of the Silu- 

 rian rocks of the South of Scotland. The Highland undulations have 

 been accompanied by very deep fractures, both longitudinal and trans- 

 versal, which are for the most part occupied by water. It follows, 

 therefore, from this undulation of similar masses, that, after passing 

 over several great mineral axes directed from W.S.W. to E.N.E., 

 and often marked by copious extrusions of granite, porphyry, or 

 greenstone, the geologist who reaches the valley of Ballyhulish, to 

 the north of Glenco, finds himself upon clay-slate of the same age 

 and character as that which he has left on the north bank of the 

 Clyde ! 



After adducing many proofs, in addition to those put forth by Dr. 

 MacCulloch, that the truly stratified rocks of the south-western 

 Highlands must have been formed under water (whether the pebble- 

 beds in the chlorite-schist of Ben Lomond, the bands of limestone in 

 the mica-schist of Inverary, or the quartzose flagstones of the Forest 

 of Glenorchy with their way-boards be considered), I have been led 

 to infer, that some of these masses, particularly the upper clay-slate, 

 might represent a portion of the Silurian system, and that others of 

 inferior position were probably accumulated anteriorly to the creation 

 of any animal whatever. 



Being desirous, however, of not mingling theoretical views con- 

 cerning the crystalline rocks of the Highlands with data which tend 

 to establish the relative order of fossil-bearing strata in the South of 

 Scotland, I defer the publication of my views on the former until 

 more exhaustive surveys of the Highlands shall have been made. 



Future researches may, as now suggested, lay open the uppermost 

 member of the Silurian rocks (which is certainly wanting in the 

 South of Scotland) in those northern tracts along the Sidlaw Hills, 

 where the lower Old Red, or Devonian, is so fully developed ; and, 

 although we may have little chance of detecting fossils in the clay- 

 slates or other rocks of the Highlands, we may yet be able by 

 further labours to determine the existence in the southern Scottish 

 counties of the very same zone of former life which has been recog- 

 nised in Scandinavia, Bohemia, on the flanks of the Malvern Hills, 

 and particularly in North Wales, as the oldest in which recognizable 

 animal remains can be detected*. 



* Murchison, Verneuil, and Keyserling, "Russia in Europe," &c, vol. i. ch. i. ; 

 Phillips, Mem. Geol. Survey of Great Britain, vol. ii. pt. 1. pp. 54, 55. Barrande 

 on the Silurian Base of Bohemia, Rep. British Assoc. 1850, Trans. Sect. p. 99 



VOL. VII. PART I. N 



