good photographs.

DAWES.--A ring-plain 14 miles in diameter, situated N.W. of Plinius, on a
nearly circular light area. Its bright border rises to a height of 2000
feet above the Mare, and includes a central mountain, a white marking on
the E., and a ridge running from the mountain to the S. wall. There are
two closely parallel clefts on the N. side of the plateau running from E.
to W., that nearer Dawes being the longer, and having a craterlet
standing upon it about midway between its extremities. At its W.
termination there is a crater-row running at right angles to it. The
light area appears to be bounded on the E. by a low curved bank.

VITRUVIUS.--A ring-plain 19 miles in diameter with bright but not very
lofty walls, situated among the mountains near the S.W. side of the Mare
Serenitatis. It is surrounded by a region remarkable for its great
variability in brightness. There is a large bright ring-plain on the W.,
with a less conspicuous companion on the S. of it.

MARALDI.--A deep but rather inconspicuous formation, bounded on the W. by
a polygonal border. A small ring-plain with a central mountain is
connected with the S.W. wall; and, running in a N. direction from this,
is a short mountain arm which joins a large circular enclosure with a low
broken border standing on the N. side of the Mare Tranquilitatis.

LITTROW.--A peculiar ring-plain, rather smaller than the last, some
distance N. of Vitruvius, on the rocky W. border of the Mare Serenitatis.
It is shaped like the letter D, the straight side facing the W. There is
a distinct crater on the N. wall. On the N.W. it is flanked by three
irregular ring-plains, and on the S.E. by a fourth. Neison shows two
small mountains on the floor, but Schmidt, whose drawing is very true to
nature, has no detail whatever. A fine cleft may be traced from near the
foot of the E. wall to Mount Argaeus, passing S. of a bright crater on
the Mare E. of Littrow. It extends towards the Plinius system, and is
probably connected with it.

MOUNT ARGAEUS.--There are few objects on the moon's visible surface which
afford a more striking and beautiful picture than this mountain and its
surrounding heights with their shadows a few hours after sunrise. It
attains an altitude of more than 8000 feet above the Mare, and at a
certain phase resembles a bright spear-head or dagger. There is a well-
defined rimmed depression abutting on its southern point.

ROMER.--A prominent formation of irr