very interesting one, and the
greater part of it can, moreover, be easily traced in a good 4 inch
achromatic. It originates in the rugged region E. of Campanus, from which
five nearly parallel curved clefts extend up to the rocky barrier,
connecting the N. side of this formation with the S.W. side of Hippalus.
The most westerly of these furrows is interrupted by a crater on this
wall, but reappears on the N. side of it, and, after making a detour
towards the W. to avoid a little mountain in its path, runs partially
round the E. flank of Hippalus A, and then, continuing its northerly
course, terminates amid the mountains W. of Agatharchides. (A short
parallel cleft runs E. of this from the little mountain to the E. side of
A.) The most easterly member of the system, originating N. of Ramsden,
enters Hippalus at the S. side of the great gap in the border, and, after
traversing the floor at the W. foot of a ridge thereon, also extends
towards the mountains W. of Agatharchides. Between these clefts are three
intermediate furrows, one of which runs N. from the N. side of the
encroaching ring already referred to, on the W. wall of Hippalus.

CAMPANUS.--A ring-plain, 30 miles in diameter, on the rocky barrier,
extending in nearly a straight line from Hippalus to Cichus. Its terraced
walls, which rise on the E. more than 6000 feet above the floor, are
broken on the S. by a narrow valley, and on the E. by a small crater. A
small central mountain is apparently the only object on a very dark
interior.

MERCATOR.--A more irregular ring-plain of about the same area, adjoining
Campanus on the S.W. Its rampart is somewhat lower, and is partially
broken on the N. by two semi-rings, and on the S. by a gap. The E. wall
extends on the S. far beyond the limits of the formation, and terminates
in a brilliant mountain mass 6000 feet in height. There is a bright
crater on the crest of both the E. and W. border. On the plain E. of
Mercator is a remarkable little crater standing on a light area, and,
just under the wall, a dusky pit connected with it by a rill-like
marking. These objects are of a very doubtful nature, and should be
carefully observed. The floor of Mercator is much lighter than that of
Campanus, and appears to be devoid of detail.

CICHUS.--A conspicuous ring-plain, about 20 miles in diameter, with a
prominent deep crater about 6 miles across on its E. rim. It is situated
on a curious boot-shaped plateau, near the S. end of th