284 
THE TERTIARY VOLCANOES 
BOOK VIII 
of the lavas between Druim an Eidhne and the Camas-unary valley. Mr. 
Harker has found a huge mass of agglomerate underlying the bedded basalts 
to the north and west of Belig, one of the hills on the west side of the 
large valley that runs from the head of Loch Slapin to Loch Aynort. This 
mass has its bottom concealed by the granophyre which underlies it ; hut it 
reaches a maximum thickness of perhaps 1000 feet, rapidly thinning out 
and disappearing. It generally resembles the Strath agglomerate, but is 
distinguished by including a large proportion of fragments of gabbro. Mr. 
Harker remarks that “a study of these agglomerates points to the exist- 
ence of both gabbros and granophyres older than the volcanic series, and 
therefore distinct from the gabbros and granophyres now exposed at the 
surface.” 
It is a suggestive fact that so many detached masses of agglomerate 
should occur around and within the areas of the great eruptive bosses of 
gabbro and granophyre. They seem to indicate the former existence of 
groups of volcanic vents in these tracts, and may thus account for the up- 
rise of such large bodies of intrusive material through what must have been 
a weakened part of the terrestrial crust. 
Further north in Skye a much smaller but more perfectly preserved 
Fig. 304. — Section of Volcanic Vent and connected lavas and tuffs, Scorr, Camas Garbli, 
Portree Bay, Skye. 
a, Rudely-bedded dull green tuff ; b, coarse agglomerate; c, prismatic basalt; d, massive .jointed basalt; e, red 
banded decomposing rock, probably of detrital origin ; f plateau -basalts, prismatic and rudely columnar ; <7, 
dyke of dolerite, somewhat vesicular, live to six feet broad ; h, basalt dyke two to three feet broad ; i, dyke 
or sill of similar basalt to h, and possibly connected with it. 
vent has been laid open by denudation on the south side of Portree Bay — a 
deep inlet which has been cut out of the plateau-basalts and their under- 
lying platform of Jurassic sandstones and shales. The great escarpment of 
the basalts has, at the recess of Camas Garbh, been trenched by a small 
rivulet, aided by the presence of two dykes. The gully thus formed exposes 
a section of a neck of agglomerate that underlies the basalts of the upper- 
half of the cliff. This neck is connected with a thick deposit of volcanic 
conglomerate and tuff which, lying between the basalts, extends from the 
neck to a considerable distance on either hand. The general relations of the 
rocks at this locality are represented in Pig. 304. 
The agglomerate ( b ) is quite tumultuous, and here and there strikingly 
coarse. Some of its included blocks measure five feet in length. These 
