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tumultuary efforts of nature, that by no means feem ade- 
quate to the production of a Giants Caufeway, or the ba- 
faltine organizations of Auvergne and Velay, feveral of 
which continue, almofl uninterruptedly, for many miles. 
This I have more particularly obferved in the folitary 
and horizontal bafaltine Jlrata that cap the high, though 
flat, vulcanic hills in Auvergne, and the adjacent part of 
Velay; as may be more particularly feen at the brows of 
thofe hills in the refpeCtive vallies. The celebrated M.de 
BUFFON, fpeaking of thefe hills,, ftyles them Des plaines 
en montagnes^ qui forment des pays au dejfus des autres 
pais(fK They alfo prove the miftake of fome naturalifts, 
who falfely afcribing to vulcanic hills in general the fame 
origin,, as to Vefuvius and ^tna^ exclufively aflign to 
them alfo the fame conical or orbicular forms. But, if I 
miftake not, the particular and relative characters of ba- 
faltine,- and other regular vulcanic organizations of the 
like kind, contradiCl a cafual and tumultuary caufe, and 
evince the neceflity of their local origin upon a more 
fteady and uniform principle. I fliall alfo further ob- 
ferve, that I never faw any certain veftige of a regular 
crater in any fpot characterized by ftmilar organizations ; 
which, as I before remarked, form, in general, integral 
parts of the mafles to which they adhere, and which alfo 
frequently manifeft an analogous ftruCture, however ir- 
regular. And fo far are they from reprefenting the ruin- 
ous fcenes of Vefuvius or ..^tna,that they often afford no 
loofe or ifolated mafles, except fragments of the columns 
(f) Hiftoire Naturelle, tom, ii. p. ii. 
of 
