livities of the inner slopes, are beautifully displayed at sunset. The
cross-valleys are more easily traced under low morning illumination; but
to appreciate the actual structure of the wall, it should be observed
under both phases. The N.W. section of the border includes many
"pockets," or long elliptical depressions, which at an early stage of
sunrise give a scalloped appearance to the crest. Except the great bright
central mountain with its numerous peaks, there does not appear to be any
prominent detail on the floor. There is a large ring-plain beyond the
foot of the _glacis_ on the W. with two craters on the E. side of it,
another on the S., and a fine rill-valley running up to its N. side from
near the crest of the W. wall. On the N. side of Piccolomini is a
remarkable group of deformed and overlapping enclosures, mingled with
numberless craters and little depressions. The plain on the N.E. is
crossed by a fine cleft.

PONS.--A complete formation of irregular shape, about 20 miles in
greatest diameter, on the S.E. side of the Altai range, in W. long. 21
deg. It consists of a crowd of rings and craters enclosed by a narrow
wall.

STIBORIUS.--An elongated ring-plain, about 22 miles in diameter, S. of
Piccolomini, with a lofty wall, broken in one place on the N. by a very
conspicuous crater. Schmidt shows a distinct crater in the centre of the
floor. I have only seen a central mountain in this position. There is a
large crater on the N.W., a ring-plain on the S.W. side, and a multitude
of little craters on the surrounding plain.

RICCIUS.--A ring-plain, 51 miles in diameter, of a very irregular type,
S.E. of the last. It is enclosed by a complex wall (which is in places
double), broken by large rings on the S. The very conspicuous little
ring-plain Riccius A is situated on the N. of it, and other less
prominent features. The interior includes a bright crater and some
smaller objects of the same class.

ZAGUT.--The most easterly of a group of closely associated irregular
walled-plains, of which Lindenau and Rabbi Levi are the other members,
all evidently deformed and modified in shape by their proximity. It is
about 45 miles in diameter, and is enclosed by a wall which on the S.W.
attains a height of about 9500 feet, and is much broken on the N. by a
number of depressions. A large ring-plain, some 20 miles in diameter,
occupies a considerable portion of the W. side of the interior; E. of
which, and nearly central,