268
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .DeC. 13,
it^
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g,
surmounted by a quartzo-scliistose mass. (2), which
presents the aspect of havhig undergone a metamor-
phosis which has affected the hard purple schists, the
conglomerate or pebbly beds, and the green schists
above them, the latter being traversed in many di-
rections by white veins of carbonate of hme. This
mass (2), not less than 300 feet thick, is amorphous,
and in colour partially resembles serpentine*. After
passing a portion of the cliff which is obscured by
detritus, a dark or almost black limestone with white
veins appears, undulating irregularly, and plunging
on the whole to the west and by north. This rock
is covered by dark schists, the Avhole probably re-
presenting the dark limestone and schists of Porto
Venere on the opposite side of the bay. These thin-
bedded dark masses are followed by the remarkable
rocks which constitute the sea-worn, amorphous and
cavernous rauch-kalk on which the picturesque old
town of Porto Telaro is built. From this point,
passing to the fort of St. Bartolommeo, there are
undulations and breaks in lower and obscurer cliffs,
in which the thin-bedded siliceous schists (slates of
Stazzemma) appear here and there beneath the rauch-
kalk. All the calcareous rocks of this series are
flanked by a vertically twisted and confused, coarse
conglomerate, made up of lumps of all the above-
mentioned rocks.
I have spoken of this highly modified range on the
east side of the gulf to show its lithological accordance
with the chief masses in the Apuan Alps, and because
it exhibits the same order of succession of mineral
masses. It is however only on the western shores of
the bay, in another parallel undulation of these lime-
stones, further removed from the chief axes of dis-
turbance, that their age can be read off by help of
some imbedded fossils. The black limestones, with
white and yellow veins and associated dark schists
(No. 3), but not so metamorphosed as on the east
side of the bay, form the chief nucleus of this western
promontory. Ranging in highly inclined and vertical
forms, by the lofty, unfinished fort of Castellana,
they strike from N.N.AY. to S.S.E., into the isle
of Palmaria, where they are largely quarried as the
black and brown marble of Porto Yenere. Among
the fossils in this rock I procured a Lima, which re-
sembles a lower secondary fossil, and certain imperfect

• I could not help suspecting the contiguity of some erup-
  

tive rock to this pecuhar limestone, and my boatman assured
me that \Yhen the sea was lower cuie of my predecessors had
discovered a pohit of porphyry.