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Mr. Defmareft, has induced him to attribute the ori- 
gin of thefe ftony columns to the matter of volcanoes 
refrigerated from fuhon, having found the Auvergne 
bafaltes placed on beds of lavas and Icorias, jull dole 
to the opening of an extinguiflied volcanoe. 
2 . I difeovered the fame appearance at Habich- 
fwald about Weiflenftein near Caflel. The top 
of the mountain, on which the famous cafeades of 
the Landgrave Charles are built, and which the 
Englidi troops made the place -of their encampment 
after the battle of Willemflahl, is hardly compofed 
of any thing but enormous pieces of lavas and Icorias. 
Somewhat lower, and near the middle of the moun- 
tain, are found the bafaltes. Many of thefe are formed 
in polyedrous pillars ; but feme, which are the neareft 
to the aforefaid lava, only con fid; of fliapelefs roundifh 
maffes. On the other fide of the mountain, and at 
a fmall diflance from the lavas and fcorije, is found one 
of the richeft coal mines I ever faw, in a bed of the 
thicknefs of eighteen feet. 
The Duke of Rochefoucault, at Paris, an eminent 
lover and encourager of natural hiftory, has likewife 
afiured me, that at Bolfena in Italy, the bafaltes are 
found near the lavas of an ancient volcanoe, and that 
the whole ifland of Sicily, chiefly on the fide of 
mount Etna, abounds with the fame. 
Hence, it may be allowable to attribute with Mr. 
Defmarcfl: the origin of the bafaltes to volcanoes. 
This opinion is further fupported from many cir- 
cumftances ; wiz;. the vitreous, and hitherto pro- 
blematical fubflance of thefe flones ; the want of 
marine bodies, and laftly, the well-known experiment 
of fome melted metals, which, when hardened, appear 
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