[ >10 ] 
'I obferved, that their fliafts, though of the ufual prifma- 
tic form, are neverthelefs fometimes wreathed, or twifted, 
like the artificial, round, and fpiral columns, that are of- 
>ten, though barbaroufly, introduced in buildings. The 
fubftance of thefe columns is, however, of the common 
fort, like that of the columns of San Giovanni, and the 
Giants Gaufeway. The town of Chillac, a few miles above 
old Brioude, on the river Allier, in Upper Auvergne, is 
alfo built on a Giants Gaufeway, confiding of high, firait, 
but unjointed columns, which are open to view towards 
the river. But I fliall give no further inftances of this 
kind at prefen t; only mufi: beg leave to obferve, before 
I quit the fubjedl of prifmatic columns, that although 
no group of them has hitherto been difcovered in our 
ifiand, yet I am perfuaded, that the mountains of Wales 
contain one; having, in my tour of that country, ol>- 
ferved feveral large pieces of fuch columns at Towen, 
on the fea coaft of Merionethfliire, not far from Dolgel- 
thy : particularly about Towen church-yard, where they 
are ufed as pods. I could not learn from whence they 
came, but Ihould fufpecd, from the character of the adja- 
cent country, that they are found in the mountains to- 
wards Dolgelthy, and probably fome where about the fa- 
mous Gader Idris. For I afterwards obferved, in my af- 
cent of that mountain from Dolgelthy,. that its predo- 
minant mafs appeared to be a fort of vitrifiable done, 
feemingly of igneous origin, and which I fhall here take 
occafion to obferve greatly prevails in North Wales, par- 
ticularly in the three Alpine Gounties of Merioneth, 
Montgomery, and Garnarvon. Having 
