£ 0 Dr. Beddoes’s Obfervations on the 
that the Author imagines the rock to be an imperfectly fufed 
granite * * * § . 1 rather confider thefe as inftances of imperfeCUy 
cryftallized granite, where fome unfavourable circumftance 
has prevented the conftituent parts from receding completely 
from one another. Experiments {hew, that almoft all granite* 
melt into a black glafs +; and perhaps it is no abufe of analogy, 
nor inconfiftent with what 1 have already remarked, to con- 
clude, that granite, in theftate of imperfeCt fufion, fhould pre- 
fent a glafly fubftance, involving the more infufible parts of 
which this {tone confifts. 
The Scheibenberg, near Konigfbruck, confifts of a {tone 
which Mr. Leske knows not whether to call hornftate J, or 
corneous porphyry §. From the defcription it appears plainly 
to be a whinftone. The colour is dark grey; it breaks into 
columnar fragments ; is hard, fine-grained, and fomrous ; little 
veins of quartz crofs it in all directions, and it frequently 
becomes porphyritic, as enclofing cryftals of feldfpath. The 
Author himfelf is afterwards aware || of its affinity to bafaltes, 
both in fubftance and from its afluming the columnar form. 
In this hill a mafs of granite is found imbedded in the whin- 
ftone, and on all fides furrounded by it, and the mafs of 
granite is in its turn in all direftions interfefted with veins and 
itripes of whinftone. Mr. Leske is much ftruck by this 
mutual and intimate incorporation ; but he makes no attempt 
to explain it. In fome inftances, he thinks an eruption has 
* Reife (lurch Sachfen, p. 330. 
f Haidinger’s Eintheilung der Gebirgsarten. Wien, 1787, p. 1*. and the 
Authors quoted there. 
J Hornfchiefer. 
§ Ibid. p. 24 — 29. No chemical characters are given. 
g ibid. P . 513, 514 
broke 
