14,000
feet above the interior. It is bounded by a linear border, approximating
very closely to an hexagonal shape, which is broken by many gaps and
cross-valleys. On the S., the S.W. and S.E. sections of the wall do not
meet, being separated by a wide valley flanked on the W. by a fine
crater, which has broken down the rampart at this place. The N. border is
likewise intersected by valleys and by a crater-row. The inner slopes are
conspicuously terraced. There is a very inconspicuous central mountain
and several large craters on the floor, some of them double. Ten have
been counted on the N. half of the interior. On the S.E. of Vieta are two
fine overlapping ring-plains, with a crater on the wall common to both.

DE VICO.--A conspicuous little ring-plain, about 9 miles in diameter,
with a lofty border, some distance E. of Mersenius.

LEE.--An incomplete walled-plain, about 28 miles in diameter, on the S.
side of the Mare Humorum, E. of Vitello, from which it is separated by
another partial enclosure, with a striking valley, not shown in the
published maps, running round its W. side. If viewed when its E. wall is
on the morning terminator, some isolated relics of the wrecked N.W. wall
of Lee are prominent, in the shape of a number of attenuated bright
elevations separated by gaps. Within are three or four conspicuous hills.

DOPPELMAYER.--Under a high sun this large ring-plain, 40 miles in
diameter, resembles a great bay open to the N.W., without a trace of
detail to break the monotony of the surface on the side facing the Mare
Humorum. When, however, it is viewed under oblique morning illumination,
a low broad ridge is easily traceable, extending across the opening,
indicating the site of a ruined wall. There is an isolated mountain at
the S.W. end of this, which casts a fine spire of shadow across the floor
at sunrise. The interior contains a massive bright central mountain and
several little hills. The crest of the wall on the E. is much broken.

FOURIER.--A large ring-plain, 30 miles in diameter, S.W. of Vieta, with a
border rising at a peak on the W. more than 9000 feet above the floor,
There are two craters on the outer slope of the N.W. wall, a prominent
crater on the S. wall, and (according to Schmidt) a small central crater
on the floor, which I have not seen. In the region between Fourier and
Vieta there are three ring-plains, two (the more westerly) standing side
by side, and on the W., towards the Mare, ar