Fig. 1. — Sicetch-map of the south-western part of the Isle of Eigg, 

 on the scale of 2 inches to the mile. 



I | BASALT 

 | DOLERITE 



PITCHSTONE 

 FELSITE 



[The above map shows how the pitchstone truncates obliquely the basalt-and- 

 dolerite succession ; also the position of the Grulin felsite-intrusion, 

 possibly representing the feeder of the pitchstone.] 



