146 
THE GEOLOGIST. 
the matured results of his observations. He agrees with Sir U. Murchison as 
far as the succession of the western gneiss, red sandstone, quartzites, (quartzite 
and fucoid bed), and limestone is concerned ; but differs from him in maintaining 
that tlierc is no upper series of an " upward conformable succession" from the 
quartzite and limestone into the eastern mica-slate or gneiss — the so-called 
*' upper gneiss." The "upper quartzite" and "upper limestone" the author 
believes \o be portions of the quartzite of the country, in some cases separated 
by anticlines and faults and cropping out in the higher ground, and in other 
instances inverted beds with the gneiss brought up by a contiguous fault and 
overhanging them. The latter condition of the strata, as well as other cases 
where the eastern gneiss is brought up against the quartzite series, have, 
according to the author, given rise to the supposed " upward conformable suc- 
cession" above referred to. In some cases where " gneiss" is said to have been 
observed overlying the quartzite. Professor Nicol has determined that the 
overlying rock is granulite or other irruptive rock, not gneiss. 
The sections described by the author in support of his views of the eastern 
gneiss not overlying the quartzite and limestone, but being the same as the gneiss 
of the western coast, and brought up by a powerful fault along a nearly north 
and south line passing from White Head (Loch Erriboll) to Loch Carron and 
the Sound of Sleat, are chiefly those which had been brought forward as afford- 
ing the proofs on which the opposite hypothesis is founded ; and in all, the 
author finds irruptions of igneous rocks, and other indications of faults and 
disturbance, depriving them, in his opinion, of all weight as evidence of a 
regular order of " upward and conformable succession." 
Prof. Nichol further argues that the mode of the distribution of the rocks 
shows that there is through Sutherland and Ross-shire a real fault, and no 
overlap of eastern gneiss of more than a few feet or yards at most; and that the 
fact of different strata of the quartzite series being brought against the gneiss 
at different places supports this view, and points to a great denudation having 
taken place along the line of fault. Though the quartzite is here and there 
a,ltered by the igneous rocks, yet it is truly a sedimentary rock, and so is the 
limestone ; but the eastern gneiss or mica-schist is a crystalline rock throughout. 
This fact, according to the author, is inimical to the "^hypothesis of the eastern 
gneiss overlying the limestone and quartzite. It has been insisted upon, that 
the strike ofthe western gneiss is different from that of the east; but the author 
remarks that the strike is not persistent in either area, and that the great 
movements subsequent to the deposition of the quartzite series have irregularly 
affected the whole region. With regard to mineralogical characters, Professor 
jS'ichol insists that both the eastern and western gneiss are essentially the same. 
Both are locally modified ^vith granitic and hornblendic matter near igneous foci: 
but no proof of difference of age in the two can be obtained therefrom. The 
alteration in bulk of the gneiss in the western area, by the intrusion of vast 
quantities of granite now observable in it, may perhaps' have caused the great 
amoujit of crumpling aud faulting along the north and south line of fault, 
dividing the western from the eastern gneiss,— a fault comparable with and 
and parallel to that running from the Morav Prith to the Linhe Locb, and to 
the one passing along the south side of the Grampians. 
Becember 19, I860.— 1. "On the Geological Structure of the South-west 
Highlands of Scotland." By T. P. Jamieson, Esq. 
In this paper the author attempts to throw light on the relations of those 
rocks which figure in geological maps as the mica-schist, clay-slate, the chlorite- 
slates, and the quartz-rock of the south.western Highlands, which range north- 
east through the middle of Scotland, forming an important feature in the 
geology of that country. An examination of these rocks, as displayed in Bute 
and Argyleshire, has led Mr. Jamieson to believe that, from the quartz-rock of 
