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cruise, or perhaps no fit opportunity offered, but to this day my 

 desire to go dredging remains unsatisfied. 



Geologically speaking, the portion of shore to which I shall 

 refer consists of the Trias, which only occurs in this north- 

 eastern corner of our island, extending southward as far as 

 County Louth, and is situated underneath the beds about 

 which we are to hear from William Gray this evening. The 

 beds opposite Macedon are the Keuper marls, both red and 

 green, whilst further towards Whiteabbey we come upon 

 almost vertical layers of red and yellow sandstone. Innumer- 

 able basaltic dykes have forced their way from beneath, some- 

 times filling irregular cracks, many feet wide, with wall-like 

 masses, at other times barely lifting the shaly layers to ooze 

 out in gentler flows. In the cross-dykes two separate flows 

 intersect one another, as is shown upon the diagram on the 

 wall. The junction is so much eroded that their relative age 

 is rather obscure, but as far as I can judge the dyke marked 

 B C is the older. During our amphibious childhood my 

 brother and I spent a large part of every summer boating along 

 our coast, and I well remember the delightful excitement when 

 our small punt ran aground, even at full tide, on those 

 familiar cross-reefs, and threatened to tilt us over into the 

 water. In those days there were but two gaps where the 

 passage could be safely attempted, but now the old black walls 

 are so worn away that a much larger boat could cross almost 

 anywhere at high tide. In fact, I am deliberately inclined to 

 put the erosion of the last 30 years as being certainly not less 

 than 18 or 20 inches. Our gardener, who has known this 

 part of the shore longer than I have, quite agrees with me in 

 this estimate, and tells me that Mr. Joynt, who lived in White- 

 house during the period I refer to, told him that he recollected 

 them very much higher still. Why these dykes that had 

 evidently withstood the waves that cut away the softer Triassic 

 rocks during the first half of the century and then remained 

 above the general plane of the shore like walls, should latterly 

 have yielded so comparatively rapidly to the action of the sea 



