312 
VOLCANOES OF THE LOWER OLD RED SANDSTONE 
BOOK V 
This division of the system has been ascertained by him to be extensively 
developed to the south of Campbeltown, and to include some small but 
interesting remains of the volcanic action which was so marked a feature in 
the areas of Lake Caledonia, lying further to the east. To the student of 
volcanic geology, indeed, this small tract at the extreme southern end of 
Argyllshire has a peculiar interest, for in no other part of the British Isles 
have the phenomena of the eruptive vents of the Lower Old Bed Sandstone 
been more admirably laid bare. Not only are there necks in the interior 
like that represented in Fig. 82; but others have been dissected by the 
Fio. 82. — View of Ciioc Garth, Southend, Campheltowu. A volcanic neck of Lower Old Eed Sandstone 
age, ahont 400 yards wide in its longer diameter. 
waves along the southern shore, and their relations to the deposits of 
fragmentary material showered over the bottom of the lake have been 
more or less clearly exposed. 
At Keil Point, a little to the east of the most southerly headland of 
the Mull of Cantyre, some reddish and purplish highly felspathic sandstones 
(a in Fig. 83) dipping towards the east are found to pass upward into 
coarse volcanic breccias (/;), which, followed eastwards, lose almost all trace 
of stratification, and are then abruptly succeeded by a neck of coarse 
agglomerate (r) measuring 25 yards from north to south, where its limits 
can be seen, and at least 12 yards from west to east. It is hardly possible 
to distinguish between the breccias to the west and the agglomerate of the 
regarded as later than tlie Coal-formation and possibly of the same age as those of the north-east 
ol Ireland. He made no distinction between the Lower Old Red Sandstone and the vonnwer 
unconformable conglomerates {quart. Jouni. Geol. Soc. vol. viii. (1852), j,. 406). " ” 
