sire to secure the throne of St. Peter from being
intruded upon by a second Pope Joan--whether there ever really was
such a personage, or whatever gave rise to the curious myth. The chair
is like an ordinary library chair, with solid back and sides,
sculptured out of a single block, and perforated in the seat with a
circular aperture. _Rosso antico_ is not what might strictly be called
a beautiful marble. Its colour is dusky and opaque, resembling that of
a bullock's liver, marked with numerous black reticulations, so minute
and faint as to be hardly visible. But the grain is extremely fine,
admitting of the highest polish.

Of black marbles--in the formation of which both the animal and
vegetable kingdoms have taken part, their substance being composed of
the finely-ground remains of foraminifera, corals, and shells, and
their colour produced by the carbonaceous deposits of ancient
forests--few kinds seem to have been used by the ancient Romans. The
_nero antico_ was the species most esteemed, on account of its compact
texture, fine grain, and deep black colour, marked occasionally with
minute white short straight lines, always broken and interrupted. It
is the _Marmor Taenarium_ of the ancients, quarried in the Taenarian
peninsula, which forms the most southerly point in Europe, now called
Cape Matapan. The celebrated quarries which Pliny eloquently
describes, but for which Colonel Leake inquired in vain, were under
the protection of Poseidon, whose temple was at the extremity of the
peninsula. They attracted, on account of the sanctuary which the
temple afforded, large numbers of criminals who fled from the pursuit
of justice, and who readily found work in them. Very fine specimens of
this marble may be seen in a pair of columns in the obscure Church of
Santa Maria Regini Coeli, near the Convent of St. Onofrio, on the
other side of the Tiber; in a pair in the church of Ara Coeli; and
also in a pair in the third room of the Villa Pamphili Doria, which
are extremely fine, and are probably as large as any to be met with.
In consequence of the quantity used in the inscriptional tablets of
monuments, for which this seems to be the favourite material, _nero
antico_ is extremely scarce in modern Rome. The _bigio antico_ is a
grayish marble, composed of white and black, sometimes in distinct
stripes or waves, and sometimes mingled confusedly together. It was
the _Marmor Batthium_ of the ancients, and two of the large columns