373 
THE CARBONIFEROUS VOLCANOES 
BOOK VI 
east of the Clyde volcanic district, and entirely independent of it, lies the 
plateau of the Garleton Hills in East Lothian, which, as its limits towards 
the east and north have been reduced by denudation, and towards the west 
are hidden under the Carboniferous Limestone series of Haddington, covers 
now an area of not more than about 60 square luilesd That the eruptions 
from this area did not extend far to the north is shown by the absence of 
all trace of them among the Lower Carboniferous rocks of Fife. A relic of 
them occurs above Lorthwick, in Midlothian, about twelve miles to the 
south-west ol the nearest margin of the plateau. The area over which the 
lavas and tuffs were discharged may not have exceeded 150 square miles. 
Small though this plateau is, it possesses much interest from the remarkable 
variety of petrographical character in its lavas, from the size and composi- 
tion of its neclcs, and from the picturesque coast-line where its details have 
been admirably dissected by the waves. In many respects it stands by 
itself as an exception to the general type of the other plateaux. 
Fig. 110. — The Bas>s Rock, a trachytic ueck Ijulougiiig to tlie Garleton plateau, from the shore 
.at Canty 13ay, 
From its proximity to Edinburgh this volcanic area has been often 
studied and described. The memoir’s of Hay Cunningham and Maclaren 
gave the fullest account of it until its structure was mapped by the Geolo- 
gical Survey. Its scenery differs from that of the other plateaux chiefly in 
the absence of the terraced contour which in them is so characteristic. The 
1 This plateau is represented in Sheets 33 and 41 of the Geological Survey of Scotland, and is 
described in the Explanation to accompany Sheet 33. 
