^5 Mr. Mills s Obfcrvations on 
{par, iimeftone, and an argillaceous fubftance mixed with 
mica; the whole tinged with iron. Continuing my walk, 
. •* 
I arrived at the foot of Beu Vinkie, which is compofed of a 
granulated whitifti chert. This mountain is faid to be the 
higheft in Hay. It is very fteep on the S.W. fide, where I 
afcended it by following the courfe of a Whyn Dyke, which 
reaches very near to the fumrait. This Whyn Dyke is fimilar 
to thofe before mentioned. It confifts of a dark-grey granular 
fubftance, which does not effervefce with nitrous acid, but 
gives fire with fteel, is {lightly magnetic, and its fpecific gra- 
vity is 2,901. It confifts alfo of a very dark granularfubftance, 
with the fame properties as the foregoing; and further, in 
fome parts, it has a granular fubftance, which includes fmall 
pieces of white chert ; other parts are of an argillaceous fub- 
ftance, fomewhat refembling hornftone, and others of a cal- 
careous fubftance which {lightly effervefces with nitrous acid. 
Here is alfo a kind of vein, containing a brown i(h argillaceous 
fubftance, and reddifti cubical calcareous fpar. The very fum- 
mit of the mountain is compofed of white cryftalline chert, 
which is not unfrequently tinged with iron. 
Loflit Hill being an objedt of great curiofity, I {hall with 
pleafure retrace our walk from Gartnefs by Glafgow Beg to 
Loflit Loch and to the Hill. Walking on the weftern fhore 
of the Loch we faw a vein of blue fhiftus, many yards wide, 
ranging N.E. and S.W. ; not far from which is an ochraceous 
earth, and much bog iron ore. Obferving, on the fouth fide of 
the Loch, the appearance of an ochry earth, we went round to 
examine it ; and near it we found an immenfe Whyn Dyke, 
ranging nearly S.E. and 1 M.W. compofed of a friable fubftance 
containing zeolite, of a black granular fubftance which gives 
fire with fteel, and a yellowifh grey fubftance, perfectly fimilar 
