292 
NOTES OF A Gf:OLOGIST IX IREL.IXD DURING AUGUST 
AND SEPTEMBER, 1857. 
By THE Rev. W. S. Symoxds, F.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 
he preparing for their vacation-rambles ; and should any think of 
visiting our Sister Isle — "Okl Erin " — the following notes may he of 
sei-vice. 
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 mu(.h country, 
breaking as many stones, gathering as many jilants, and catching as 
many salmon as time and circumstances would permit. A\'"e were fortu- 
nate in our combination of naturalist and sportsman, 1)ut as tliese 
notes are intended solely for the naturalist, we leave our " salmon 
struggles " unrecorded — at least in the pages of the Geologist. 
We travelled by 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 A'isit the Cambrian rocks 
of Aiiglesea. 
AVe never saw a more instructive example of contortion and twisting 
of rocks than is displayed at the South Stack Lighthouse, of which a 
ffood sketch is mvcn in Sir R. Murchison'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 gi-eat 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. We were 
a'itouished at the magnitude of the works for the breakwater — eight, 
and, we believe, ten tons of gunpowder have been used in the quarries 
for a single explosion ; and at one Idast more than 100,000 tons of 
quartzite have been hurled downwards from the mountain-side, while 
upwards of six millions of tons of the rock have been buried beneath 
the waves that wash the shores of Holyhead. Mr. Robert jVIallet read 
a ]ia]ior afterwards at Dulilin, on earth -Avavcs caused by earthquakes; 
