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 the rocky mountain barrier associated with the last two formations.  Its walls rise about 9000 feet above a sunken floor, on which there is some faint detail, but apparently nothing deserving the distinction of a central mountain.  The plateau on the N. is cut through by a fine broad valley, which has obviously interfered with a large crateriform depression on its southern edge.  A cleft runs from a small crater W. of the plateau up to this valley, and extends beyond to the W. wall of Capuanus.  There is also a delicate cleft crossing the region S. of Cichus to the group of complicated formations S.W. of Capuanus.  As already mentioned, the great Hesiodus cleft is associated with the Cichus plateau.

CAPUANUS.—­A large ring-plain, about 34 miles in diameter, E. of Cichus, with a border especially remarkable on the E., where it rises more than 8000 feet above the outside country, and includes a large brilliant shallow crater.  It is broken on the N.W. by a small but noteworthy double crater; and on the S. its continuity is destroyed for many miles by a number of big circular and sub-circular depressions and prominent deep valleys, far too numerous and complicated to describe.  The level dusky interior contains only a low mound on the S., but is crossed by some light streaks running from N. to S.