Affinity between Bafaltes and Granite . ^ 
decay of the rocks they infpe£ted At all events, lavas in 
abundance fhew, that fire is capable of producing any required 
degree of compa&nefs +. 
I fhall conclude this induction of particulars with an obfer- 
vation lately published by one of our raoft intelligent minera- 
logical travellers. 44 Among the ancient black ftones, the 
44 compound fpecies are moft frequent. They often confift of 
44 a kind of granite , in which the fcaly black fhoerl predominates 
44 fo much, that the whole mafs appears black. It is accompa- 
44 nied by white feldfpath of fofmall a grain, and fo entangled 
44 among the fhoerl, as to be fometimes fcarcely diftinguifhable. 
44 The feldfpath itfelf is fometimes tranfparent, and by tranf- 
44 mitting the colour of the fhoerl, in which it is imbedded 
<4 (empate) appears black Sometimes fcales of black 
44 mica occur. The conftituent parts do not always obferve 
44 the fame proportion ; and when the quantity of feldfpath 
44 increafes, the appearance of a real grey or red granite is pro- 
44 duced. Hence we have veins and fpots of grey granite in 
44 almoft all the dark-coloured rocks that pafs under the 
44 denomination of bafaltes. Thefe veins have very much 
44 embarrafled thofe naturalifts who maintain that all bafaltes 
44 has been produced by fire.” This circumftance, however, 
according to my view of the fubjeft, is far from embarraffing : 
I confider it as a ftrong proof of my opinion, fince it feems to 
involve this confequence, that, if bafaltes proceed from fufion, 
granite alfo muft. Specimens, fuch as thofe here defcribed, I 
fliould place near granular bafaltes, like that of Cape Fair- 
head. 44 In blocks of ancient bafaltes,” proceeds M. Dolo- 
* “ Though partial fpots of this granite are often, friable, efpecially about the 
furface, yet in general it is very hard.” Strange, ubi fupra, p. 9. 
f See Dolomieu, Ifles Ponces, p, 139. 
MIEU,. 
