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ASSOCIATED ROCKS OF PORTHALLA COVE.
461
becoming more siliceous. All
these beds I regard as newer
than the rocks of Nelly's Cove
and those immediately to be
described, both the latter hav-
ing a more considerable dip to
the S.E. or E.S.E. They have
probably been let down by a
pair of faults.
We now come to the tract
which forms the main subject
of this paper, extending east-
ward from " the fault " to Mr.
Hickes's quarry, about 5 of a
mile in all. This is illustrated
in sections figs. 2 and 3. These
rocks are considered by Prof.
Bonney to represent the " Ar-
chaean" metam Orphic series of
the Lizard Head, which he di-
vides into three groups, as
under : —
The micaceous or lower
group,
The hornblendic or mid-
dle group,
The granulitic or upper
group.
He thinks he can identify
here the " micaceous " group,
containing in its upper part a
stratum of granulite similar in
character to the upper group,
and also the middle or horn-
blende " series, in which occurs
the serpentine. This latter,
he maintains, is decidedly in-
trusive.
Thus Prof. Bonney considers
that two out of the three sub-
divisions of his Lizard Archaean
series are represented here. To
me the evidence seems all the
other way. In the first place
the rocks are very distinct, both
chemically and mineralogically,
as I shall show hereafter ; of
much greater importance, how-
ever, is the difi^erence of strike.
Q.J.G.S. .Sro..59.
° o
( Hickes s Quarry.
( Hornblende schist.
—Serpentine.
-Hornblende schist.
■* Serpentine.
—Hornblende schist.
■• Serpentine,
--Hornblende schist.
-Serpentine.
-Serpentine.
Eed shale.
M.±.
_" Micaceous Group ^ofj
Prof. Bonney.
-Fault No. 2.
i Non-micaceous base
"\ . of Prof, Bonney's
( Micaceous Group,
- Granulitic group.
.Fault No, 1.
Porthalla slates.
I : — ———.-Porthalla.
to
I
5s^
o