85" 



E 



"-20° 



E 



55" 



W 



120 Proceedings of the Royal Irish Academy. 



Malahide Strand — contimied. 



341 Set of Dolomite beds, dipping towards nortli. Direction, 



342 Great Dolomite joint, Hi-defined, in slialy limestone, 



343 Fault running towards sustaining wall of road, 



(CarrickhLlI Tower just in sight.) 

 Direction of beds Nm- 92"-93° E. Dip to north at 

 27". 



344 Jointing relatively rare here, but markedly vertical and 



without spar, 16"-17" E. 



Recurrence of Dolomite beds here. 



345 Dolomite joint, apparently the continuation of preceding 



one, evidently very extended and important, . . 13"-14" E. 



346 Another very important Dolomite joint, here very 



marked, .' 33"-34" E. 



347 Extremely well-marked, very continuous and open 



jointing, largely intervalled, cutting these beds, . 17"-18° E. 



348 Accompanied by a system of "gashes," filled with spar, 



and rumikig on the west side of it. Main direction, . 52"-53° E. 



349 Crossed by open jointing at ..... 72°-73° W. 



350 Two other parallel "gash" systems — one to the east, 



with jointing, and the other to the west, without, 



having a direction, ....... 19° E. 



These two systems of main jointing block out the 

 rocks here into great parallelopideds. 



351 Bedding nearly horizontal here, and Dolomite with 



marked joiating at, ...... 3"-4° W. 



352 Joint with 2 to 3 in. thick Dolomite lining, in horizon- 



tal Dolomite shale, ....... 1" "W. 



A parallel at 5 yards to west, ..... „ ,, 



353 Joint to west of last, 8 in. broad, Dolomitic and irregular, 12° "W". 



354 Another joint to west of last, 3 in. broad, Dolomitic and 



iiTegular, ........ 7°-8" E. 



355 Close under roadway, 2 in. Dolomite joint, looking to- 



wards Ireland's Eye, ...... 25°-26" "W. 



7 or 8 other joints between this and the road, seemingly 

 parallel, and rimning towards the nose of Howth. 



356 Great fault here, Dolomitic on both sides, with throw, . 78°-80° W. 

 Beds dipping on north side at about 30". 



357 On shore side, in connexion with a great joint, . . 56°-57° W. 



358 The Dolomite on the south side, thickly scored by thin 



spar jointing, at ...... . 28°-28° E. 



359 The limestone beds coming in again, a few yards to the 



south of fault. Joints in it at . 



360 Great open joint under road, at about .... 

 Here grey, crystalline limestones occm-, with " gash" 



veins, one of which near Dyke gave 



361 Crossed by a set of sparry joints, short, and 5 in. thick, 



362 Another " gash" vein system, 



96° 



E 



85° 



W 



4" 



W 



20° 



E 



7°-8° 



E 



