e 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.

RAMSDEN.--This ring-plain, 12 miles in diameter, derives its importance
from the remarkable rill-system with which it is so closely associated.
Its border, about 1800 feet on the W. above the outside surface, is
slightly terraced within on the E., where there is an unrecorded bright
crater on the slope. The two principal clefts on the S. originate among
the hills E. of Capuanus. The more easterly begins at a crater on the N.
edge of these objects, and runs N. to the E. side of Ramsden; the other
originates at a larger crater, and proceeds in a N. direction up to a
bright little mountain S.W. of Ramsden; when, swerving to the N.E., it
ends at the W. wall of this formation. This mountain is a centre or node
from which three other more delicate branches radiate. On the N., three
of the shortest clefts pertaining to the system are easily traceable from
neighbouring mountains up to the N. wall, which they apparently partially
cut through. The E. pair have a common origin, but open out as they
approach the border of Ramsden.

VITELLO.--A very peculiar ring-plain, 28 miles in diameter, on the S.
side of the Mare Humorum, remarkable for having