338
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Feb. 21
merely a result of the mixture of the soft surface of the gypsum
with the mechanical detritus first deposited ou it.
(7.) On the opposite side of the creek, which makes a small break
in the section, is a thick bed of marl, whose dip appears to be the
same with that of the gypsum. In general character it resembles
the marl underlying the gypsum. In some parts it is greenish, and
homogeneous in texture ; in other parts it is brecciated, and some layers
haA'e a brownish colour and shaly texture. In some parts it is highly
gypseous and contains layers of granular gypsum, one of which is
black, its colour being due to a small proportion of coaly or bitumi-
nous matter.
(8.) Beyond the marl the shore is occupied for a short space by
boulder clay. Beyond this it shows a great thickness of dark shales
with calcareous bands, containing a few small shells ; they dip to the
E.S.E. at a high angle, and overlie the gypsum. They are succeeded
by a thick band of very hard grey and brownish sandstones and shales,
containing a few fragments of plants stained by carbonate of copper.
These are again overlaid by dark shales, and these by an enormous
thickness of grey and brown sandstone and shale. Some of the shales
in this part of the section have assumed a kind of slaty or rather
prismatic structure, which I have endeavoured to represent in the
Fig. 3.
Shales with prismatic structure.
sketch, fig. 3.
At Ship Harbour, four miles di-
stant from Plaister Cove, the series
last mentioned is seen to contain
thick beds of grey flag and finely
laminated shale, and also a bed of
black shale with shells of Modiola
and Cypris. The coast sections
show no beds higher in the series
than these last; but farther in-
land they appear to be succeeded,
m ascending order, by a great de-
posit of grey sandstone and shale *
containing a bed of limestone and a
smaller bed of gypsum, the former
abounding in Prodiicta Lyelli and
other characteristic shells of the
lower carboniferous system. These
are followed by true coal-measures,
containing Lepidodendron, Cala-
mites, Sigillaria, Stigmaria, &c.
In examining this section, an observer is struck by the contrast
between the hardened and altered sandstones and shales, and the soft,
light-coloured marls associated with the gypsum. Though not
uncommon in the gypsiferous series, this contrast is, in the case of
Plaister Cove, more striking than usual, in consequence of the com-
paratively high state of induration of the sandstones and shales. It

• The ' Millstone grit' of Mr. Brown : see his paper on Cape Breton, Jouinal
  

of Geol. Soc. vol. i. p. 211.
Dip of beds S. "5° East.
a. Joints, strike E. and W. Dip S.