Jome Strata in Ireland and Scotland. . 
pieces are found which contain minute fpecks of fhoerl 
and of a calcareous fpar ; fpecific gravity 2,484. I n fome 
parts it is of a whitifh grey calcareous fubftance, fpecific 
gravity 2,542 ; in others of a pale greenifh grey, whofe 
lpecific gravity is 2,322, and which does not effer- 
vefce Wlth nitrous acid, but contains threads of calcareous 
fpar, and is fometimes alfo found coated, and fometimes 
fpangled, with pyrites, and then its fpecific gravity is j n . 
creafed to 2,833. Throughout this great mafs, nodules 
of a yellowifh grey colour are found, which do not effer- 
vefce with acids, or give fire with fteel, and which are in 
appearance very fimilar to fome kinds of Derbvfhire toadftonc • 
fpecific gravity 2,652. Other nodules are alfo met with’ 
of a kind of indurated clay, coated like the geodes, and tinged 
with iron. The central part, which is the fofteft, after befoo- 
drawn up, and lying fome time expofed to the affion of the 
air, decompofes, and moulders into a friable earth, fimilar to 
that which is found on the furface near Belfaft, and various 
other places in the county of Antrim, and in the ifland of 
Going from Gnrtnefs to the lead mines at Ardaehie, I paffed 
afgow Beg, where is a lead vein, formerly wrought, ranging 
between limeftone fides E.S.E and W.N.W. : a fmall Whvn 
yke croffes this vein, running nearly S. 3 .W. and N.N.E.. 
arther fouth is an old open caft in a lead vein, ranging E.* 
and W., and hading S. At fome diftance from hence is Arda- 
ch.e mine. This vein, which has formerly been much 
wrought has the fame range and hade as the preceding, and 
is crofied by a Whyn Dyke, ten feet wide, which throws the 
vein nine feet from its general diredion. Proceeding from 
nence over moory ground, near Allala, faw a dead vein of 
