THE 



SCIENTIFIC PROCEEDINGS 



OF THE 



ROYAL DUBLIN SOCIETY. 



Vol. XV. (U.S.), Ho. 15. OCTOBER, 1916. 



ON THE MODE OF OCCUERENCE AND ORIGIN 

 OF THE ORBICULAR GRANITE OF 

 MULLAGHDERG, CO. DONEGAL. 



BY 



GRENVILLE A. J. COLE, M.R.I.A., F.Gfc&£* 



PROFESSOR OF GEOLOGY IN THE ROYAL COLLEGE OF SCIENCE FOR IRELAND. 



(PLATES IV-V.) 



[A uthors alone are responsible for all opinions expressed in their Communications.] 



DUBLIN : 



PUBLISHED BY THE ROYAL DUBLIN SOCIETY, 



LEINSTEK HOUSE, DUBLIN. 



WILLIAMS AND NORGATE, 



14, HENRIETTA STREET, COVENT GARDEN, LONDON. W.C. 



1916. 



Price One Shilling. 



