Prof. C. Lapworth—The Secret of the Highlands. 127 
This cliff-section is merely the northern edge of a long and broad 
basin of Limestone which occupies the flat ground of Tor Leath and 
Eriboll House lying to the south of the promontory. To the westward 
of the basin its strata are truncated by the waters of the Loch. To the 
eastward, however, the outer edge of the basin is bent abruptly up- 
wards, and the underlying strata again emerge in their natural order 
from below the limestone, between the latter and the Sutherland 
gneiss in the mountain slopes to the south-east of Ant-Sron. The 
beds are more or less looped and folded, and towards the summit of 
the ascent are vertical or even inverted. But by a careful study of 
the ground, which is comparatively bare, the stratigraphist is able 
to read off the descending succession in regular and unbroken order. 
The dark limestones (VI. b.) here fringe the eastern edge of the 
basin. These pass downwards through the yellow band (IV. a.) 
into the Salterella grit (III), which is often very conspicuous. 
Next emerge the yellow and buff-tinted flagey beds, dolomites, and 
shales of the Hielem beds (II.), with their fucoids and worm-tracks. 
Rising out from below these to the east appears the Pipe-rock (1. d.) 
of the Lower Quartzite, charged with its hosts of rounded Anne- 
lide tubes. Next rises to day the massive white Quartzite (iI. ¢.) 
so conspicuous at the opposite side of the Loch. Below follows 
the faintly-coloured and more flagey quartzites of the underlying 
zone (JI. b.), and lastly from beneath the whole, rises out the thin 
basal conglomerate itself, with its quartz-pebbles, and fragments of 
coloured shales. 
This conglomerate rests at once upon the highly crystalline or so- 
called igneous rock of the Sutherland gneiss upon the platform 
above the ridge, where a narrow island of quartzite is surrounded 
by the crystalline “igneous rock,” and is separated from it by the 
basal conglomerate, the visible phenomena affording very clear evi- 
dence of a distinct unconformity between the two series. 
In this locality, therefore, we have not only a complete demon- 
stration of the identity of the so-called Lower and Upper Quartzites, 
but proof that the Lower Quartzite (and of necessity the whole of 
the fossil-bearing series) is of newer age than the “igneous rock” 
of the Sutherland gneiss. 
Hence, whether we agree with Murchison, Heddle, and Callaway, 
that this so-called igneous rock is an integral part of the Upper 
Gneiss, or whether, on the other hand, we accept Nicol’s view that 
it is an intrusive rock of much more recent date, the final result is 
precisely the same. The unaltered fossil-bearing Durness-Hriboll 
series is demonstrably newer than the Sutherland gneiss. If, there- 
fore, as commonly believed, the Sutherland or Upper Gneissic Series 
is merely part and parcel of a single rock-formation which extends 
over the Highlands generally, then the whole of the metamorphosed 
and altered rocks of the Highlands must be of ‘“ Pre-Silurian” age. 
Here, then, we have a result which is diametrically opposed to 
that which we obtained in the Durness area. That is to say, if 
we rely solely upon ordinary evidences of superposition, we can ap- 
parently demonstrate in one area of the North-west Highlands that 
