File:The Quarterly journal of the Geological Society of London (13204972153).jpg

RECENTLY EXPOSED NEAR BEAUMARIS.
473
denly became extremely coarse,
the felsite fragments being some
9 inches in diameter ; the gene-
ral appearance suggests that this
may be an agglomerate rather than
a conglomerate. There is also a
dyke of a compact dark rock with
scattered crystals of whitish fel-
spar often about half an inch long,
resembling very closely a dyke in
a quarry above the Bangor Ceme-
tery *. Beyond this spot, for
some distance the drive crosses an
open field, and the slope is over-
grown with vegetation of long
standing ; so, as there was no pro-
bability of any more exposures that
would be of interest, I did not
follow it further. On the crest of
the ridge, about 150 yards to the
N.W. or W. of the above rocks, is
schist of the ordinary type.
. I have examined five slides cut
to illustrate this series of grits : —
one, from the mass nearest the
schists,to represent the normal rock
of this part ; another, from near the
same, to examine more especially
the included fragments ; a third
from the greenish grit associated
with argillite, near the bridge on
the western side ; and a fourth to
illustrate the red felsite grit east
of the bridge, cut from a part
where the fragments are often
about the size of small peas. "We
find, in these, grains of quartz, fel-
spar, and several varieties of tra-

• I hare not examined this microsco-
  

pically, as I could not have got a speci-
men worth cutting without much de-
facement of the ice-worn surfaces. The
" Cemetery " dyke lias in its ground-
mass a considerable family likeness to
the one already described, but is a little
coarser, and the augite is better pre-
served. The larger felspar crystals ap-
pear to be of the same species as those
in the ground-mass, but are more de-
composed, and partly replaced by secon-
dary microliths.
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