Mr. Mii.ls’s Olfervathns on 
to Bufh-Mills, lava is continually feen, either in folid maftes, 
forming the bafis of the vegetable foil, or die in tumblers 
difperfed over the furface. 1 employed two days in ftudying 
the various appearances at the Giant’s Caufeway, and regretted 
being obliged to quit it fo -haftily. So much has been already 
faid upon this fpot, that 1 will only venture to rcmsik, thrit 
the red ochry joints between the beds of rude lava, and the 
different heights at which the bafalt pillars are feen, give pro- 
bability to the conjecture, that the whole mafs has been the 
produce of feveral fucceffive eruptions. 
I embarked at Port Ballintrea, and after twelve hours failing 
arrived at llay. My objed was to infpeft the lead mines which 
were open, and to view the other mineral veins in feveral parts or 
the ifland. It was impoffible to do this, without at the fame 
time noticing the Angular appearance of thofe mafles, which 
run in a kind of veins in various directions, and are called 
Whvn Dykes. As my attention was principally engrafted by 
the former, and my ft ay in the ifland very fiiort, I only cur- 
forily remarked, that the latter had in fome places a bafaltic 
y 
appearance ; but my time did not admit of a minute inquiry 
into their nature. 
On my return from Hay I landed at Portrufh; and, in 
my way to Ballycaftle, I viewed the Giant’s Caufeway from 
the top of the cliffs, and was much ftruck with feeing below 
me, in the fourth or eaftern bay, a kind of Whyn Dyke, which 
ran into the fea towards the N.N.E. 
Examining the cliffs at Ballycaftle, 1 found the horfes (or 
faults) of which there are feveral between the coals, were veins 
of lava (refembling the Whyn Dykes of Hay) ftanding ver- 
tically, interfering the various ftrata of coal and freeftone, 
and running into the fea. The largeft: of the veins or Whyn 
Dvkes 
