122 



Proceedings of the Royal Irish Academy. 



387 



388 



389 

 390 



391 

 392 

 393 



394 

 395 



396 



397 

 398 

 399 



400 

 401 



402 

 403 



404 



405 



406 

 407 

 408 

 409 



410 



411 

 412 

 413 

 414 

 415 



2r 



E 



54°-5o° 



E 



26°-27° 



E 



20° 



W 



10 -ir 



E 



7°-8° 



E 



6°-7° 



E. 



Donabate Coast — continued. 



"Gash" joint, filled -svitt quartzose matter, in boss of 

 conglomorate, 400 yards north of Tower, . . . 62''-63' 



Dyke in slate rock, looking towards Dalkey Is., with dip 

 towards north at about 70", .... 



" Gash " vein in slate rock, ..... 

 Vertical and repeated simple jointiag, dipping south at 



about 70°, and crossing these rocks, . 

 Well-marked jointing, crossing these rocks, 



Fault, well-marked, dipping north, and running towards 

 Tower on Ireland's Eye, .... 



Fault, 12 to 15 yards north of last mentioned. 



Great -vertical feldspar joint, crossing the slate rock 



1 ft. thick in places, ...... 67°-6 



Great fault here, crossing last -mentioned, stopping it, 

 and running towards Ireland's Eye, ... 



Thin, simple, vertical jointing occurring here, 



Ragged vertical jointing occurring here, 



Great fault here, giving rise to a little inlet looking to 

 wards north end of Lambay, .... 



Faidt in cave, with well-marked throw of beds, . 



Great vertical, gaping joint (beyond little creek), pro- 

 ducing a cave with blow hole ; looks towards stack of 

 L-eland's Eye, ........ 7°-8' 



Dyke in banded shales near Tower, .... 



Great fault at contact of slate rock with banded shales, 

 forming inlet (conglomerate mass), .... 



Inlet, about 200 yards south-west of Tower, with ap- 

 proximate direction, ...... 



Old shaft, about 100 yards from Tower, apparently on a 

 fault running towards Baldoyle and Sugar-loaf 

 Mountain, Cave with fault i-unning towards Howth, 7°-8 

 Carboniferous shales, vertical, strike IST™' 52°-53° "W". 



„ ■, 66° W. 



» =, 60° W. 



Jointing here sparse and unimportant, . 



Fault with lining, dipping south at about 40°, 

 JoLuting running towards Maitello Tower on Portrane 

 shore, ......... 



"VTell-marked fault, running to north of Lambay Is., 

 with slight dip to south, ...... 



Well-marked joint, producing a little inlet, . . 

 Thin jointing, running towards east side of Howth, 



Jointing frequent and vertical, with spar lining in face 

 of Lambay Is., ....... 



7°-8° 



E. 



83°-84° 



W. 



83°-S4° 



W. 



87° 



W. 



27°-28° 



W. 



7°-8° 



E. 



45°-46° 



E. 



7°-8° 



E. 



20° 



E. 



8°-9° 



E. 



29°-30° 



E. 



88° 



W. 



39°-40° 



E. 



o3°-o4° 



W. 



Xm. S'"- 





12°-13° 



E. 



9°-10° 



E. 



10°-11° 



E. 



