[ 19 ] 
have lately occurred to me in Auvergne and Velay, which 
have never yet been conlidered, and of which I fliall 
hereafter give an account) it feems, I fay, evident to me, 
that fuch regular bodies have been generated locally, and 
not in the midft of thofe violent convullions of Nature, 
which are commonly affigned for the origin of vulcanic 
mountains in general. That the principle of organiza- 
tion, whatever it be, operates locally, in the formation of 
thefe bodies, appears, I think, fufficiently evident from 
the regular difpolition and other particular chara6lers of 
their groups. For notwithftanding the various dire(5tions 
of the columns, and maffes compofed of them, in the dif- 
ferent groups, as I have before obferved ; yet, in other 
refpedts, the greateft regularity of difpolition is common- 
ly obfervable. They form Jirata^ which are uniformly 
organized, difpofed in particular dire6lions, and often 
conftant in the fame to a great extent. Thefe Jlrata not 
only manifelt a parallelifra between their regularly fi- 
gured parts, but in their whole aggregates ; which often 
form extenfive horizontal beds, and of an equal thick- 
nefs throughout. This parallelifm is alfo equally re- 
markable in groups that are compofed of many Jirata% 
as I have particularly obferved in thofe of Murat, and the 
Caftle Hill of Achon, in Upper Auvergne; in which the 
columnar Jlrata are not only parallel in themfelves, but 
preferve, in their pofition, a parallelifm with the other 
Jlrata of the refpe6Uve groups, which lie in regular ftages, 
one above the other : and fince thefe groups commonly 
form, in a manner, integral parts of the mafies, or moun- 
D 2 tains, 
