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NOTES OF A GEOLOGIST IN lEELAXD DUEIXG AUGUST 

 AND SEPTEMBER, 1857. 



By THE Rev. W. S. Symoxds, E.G.S., 



Rector of Pendock, President of the Malvern Natural History Field Club. 



As the summer approaches, many of the readers of the Geologist will 

 be j)reparing for their vacation-rambles ; and should any think of 

 visiting our Sister Isle — "Old Erin " — the following notes may be of 

 service. 



We started on a bright August morning of last year for the meeting of 

 the British Association for the Advancement of Science, held in 

 Dublin, and with the intention of travelling over as much country, 

 breaking as many stones, gathering as many plants, and catching as 

 many salmon as time and circumstances would permit. We were fortu- 

 nate in our combination of naturalist and sportsman, but as these 

 notes are intended solely for the naturalist, we leave our "salmon 

 struggles " unrecorded — at least in the pages of the Geologist. 



We travelled hj Conway and Bangor to Holyhead, and as it was 

 blowing a gale of wind when we arrived, we determined to wait until 

 the sea was calmer, and, in the meanwhile, to visit the Cambrian rocks 

 of Anglesea. 



We never saw a more instructive example of contortion and twisting 

 of rocks than is displayed at the South Stack Lighthouse, of Avhich a 

 good sketch is given in Sir R. Murcliison's " Siluria." It is indeed 

 a rugged coast ; and the terrible Bay of Caernarvon to the south has 

 been the locale of more shipwrecks than any other in the British Isles. 

 We visited the grand quarries of quartzite, worked on a gigantic scale 

 for the great breakwater. Here, as the geologist approaches the 

 quarry from Holyhead, is a greenstone-dyke traversing the quartzite 

 with a singular vein of pink decomposing felspathic rock. AVe were 

 astonished at the magnitude of the works for the breakwater — eight, 

 and, we believe, ten tons of gunpowder have been used in the quarries 

 ibr a single explosion ; and at one blast more than 100,000 tons of 

 quartzite have been hurled downwards from the mountain-side, while 

 upAvards of six millions of tons of the rock have been buried beneath 

 the whvos that wash the shores of Holyhead. Mr. Robert Mallet read 

 a paper aftevwards at Dublin, on earth-waves caused by eartliquakos ; 



