:o8 
THE TERTIARY VOLCANOES 
BOOK VIII 
In G-arbh Eilean, where the thickest mass of erupted material presents 
itself, at least three sills may be observed. Some low reefs that run parallel 
with the northern coast of the island consist of coarse ophitic gabbro in 
two or more sheets which have been intruded between the Jurassic shales. 
(From a Photograph by Colonel Evans.) 
