chap, xliv THE GABBRO OF ARDNAMURCHAN AND MULL 
355 
stripped off from the platform of sandstones and schists which they un- 
doubtedly at one time covered, and the few outliers of them that remain lie 
at some little distance from the margin of the gabbro area (ante, p. 216). 
Nevertheless, we are not without some indications of them underneath the 
gabbros. I have alluded to the basalts that lie at the base of the eastern 
cones. As we follow the bottom of the gabbro southward round the flanks 
of the hills, dull compact black shattery basalts, with a white crust, appear 
from under the more crystalline sheets. These at once remind one of the 
altered basalts of Skye and Mull. On the west side also, beds of basalt 
emerge from under the gabbro, but they have been so veined and indurated 
by the granopliyre of that district, that their relations to the gabbro are 
somewhat obscured. If we could restore the lost portions of the plateau, I 
believe we should find the gabbros of Eum resting on part of the volcanic 
plateau, and some of the gabbro-beds prolonged as sills between the sheets 
of basalt. 
3. The Gabbro of Ardnamurchan 
The promontory of Ardnamurchan reveals as clearly as the flanks of 
the Cuillin Hills, though in a less imposing way, the relations of the gabbros 
to the plateau-basalts (Map VI.). From the southern shore at Kilchoan to the 
northern shore at Kilmory, bedded basalts, of the usual type, amygdaloidal 
and compact, weathering into brown soil, may be followed along the eastern 
slopes of the hills, resting upon the schists and Jurassic series of western 
Argyllshire. These rocks are a continuation of those that cap the ridges 
further to the south-east and cross Loch Sunart into Morven. They dip 
westwards, and followed upwards in that direction, they soon present 
the usual marks of alteration. They weather with a white crust and 
become indurated and splintery. Sheets of dolerite with many veins and 
dykes of basalt run between and across them. Bands of gabbro make their 
appearance, and these, as we advance westwards, increase in number and in 
coarseness of grain until this rock, in its rudely bedded form, constitutes 
practically the whole of the promontory from Meall nan Con to the light- 
house. Many admirable sections may be seen on the coast-cliffs and in the 
rugged interior, showing the irregular bedding of the gabbro, and how prone 
this rock is to develop its component minerals in bands or ribbons, sometimes 
made up of large crystals, as in Skye, Eum and Mull. 
4. The Gabbro of Mull 
In the island of Mull, the conclusions to which the geology of the other 
volcanic districts leads us as to the position of the gabbros in the series of 
volcanic phenomena, are further confirmed. The first geologist who appears 
to have observed the relation of these rocks in that island was Jameson, who 
classed them under the old name of “ greenstone,” including in the same de- 
signation rocks now termed dolerites and gabbros. He ascended one of the 
