O'E/EiLLY — On Jointing in RocJcs about Dublin, ^c. 131 



No. of 





Magnetic 



Jointing 





Bearing 





461 



20° 



30' 



E. 



525 



20° 





E. 



527 



17° 



30' 



E. 



640 



17° 



30' 



E. 



Locality of Occurrence. 



Observations. 



Number of Directions observed, 10. 

 191° -f 10 = 19° 6' E. mean value. True bearing, 1° 14' W. 



308 



20° 30' 



E. 



Malahide Coast 



361 



20° 



E. 



)> j> 



388 



21° 



E. 



Donabate Coast 



404 



20° 



E. 



)) )> 



461 



20° 30' 



E. 



Skerries Coast. 



Number of Directions observed, 5. 

 102° -i- 5 = 20° 24' E. mean value. True bearing, 0° 56' "W. 



331 



23° 30' 



E. 



Malabide Shore. 



335 



24° 30' 



E. 





338 



22° 30' 



E. 





339 



23° 30' 



E. 





423 



25° 30' 



E. 



Eush Coast. 



445 



24° 30' 



E. 



Lough Shinney Coast. 



450 



24° 30' 



E. 



i> >> )> 



Number of Directions observed, 7. 

 168° 30' ^ 7 = 24° -04' mean value. True bearing, 3° 44' E, 



291 



40° 30' 



E. 



St. Dolough's Quarry, 



297 



38° 



E. 



Malahide Shore. 



298 



42° 30' 



E. 



;> )> 



299 



42° 



E. 



?» >> 



300 



39° 



E. 



i> )) 



306 



40° 30' 



E. 





314 



41° 30' 



E. 



j> )> 



326 



42° 



E. 



;> 



382 



42° 30' 



E. 



Donabate Coast. 



409 



39° 30' 



E. 



)) )> 



471 



42° 30' 



E. 



Donnybrook, Dodder Eiver 



479 



37° 30' 



E. 



J? )) 7? 



500 



43° 30' 



E. 



Raheny Quarry. 



509 



41° 30' 



E. 



Palmerstown. 



530 



44° 



E. 



Eathgar Quarry. 



534 



37° 



E. 



Leixlip. 



545 



38° 30' 



E. 



Feltrim Quarry, 



549 



43° 30' 



E. 



)> ,, 



551 



41° 30' 



E. 



)> >> 



552 



43° 30' 



E. 



)' »> 



554 



42° 30' 



E. 



)> >; 



R.I. A. PROC, SER, 11., VOL. IV. — SCIENCE, 



