tions
of libration. Their position cannot be closely defined, but the principal
deviation from circularity extends from about S. lat. 10 deg. to the
region on the limb opposite the S. border of the Mare Crisium.]

VENDELINUS.--The second great enclosure pertaining to the meridional
chain--a magnificent walled-plain of about the same dimensions as the
last. It is bounded by a very irregular rampart, which, under evening
illumination, is especially noteworthy, though nowhere approaching the
altitude of that of Langrenus. Its continuity on the W. is broken by the
great ring-plain Vendelinus C, about 50 miles in diameter, a formation
resembling Langrenus in miniature. This is hexagonal in shape, and has
many rings and depressions on its W. wall. South of Vendelinus C, the
wall of Vendelinus runs up in a bold curve to the fine terraced ring-
plain Vendelinus B, and is surmounted by a bright serpentine crest, and
traversed by several valleys running down the slope to the floor. B has a
small crater on its N. wall, and another in the interior. There is a wide
gap in the S. border of Vendelinus, which is partially occupied by
another somewhat smaller ring-plain, bounded by a southerly extension of
the E. wall, which includes on its outer slope many craters and other
depressions, and abuts near its N. end on the large ring-plain Vendelinus
A, which has a prominently terraced wall and a large bright central
mountain. Between A and C extends a plateau that may be regarded as the
N. limit of the formation, including, among other minor details, a fine
cleft, which traverses it from N. to S., and ultimately extends to a
group of craters on the floor. On the S. side of the interior is one
large ring-plain, flanked on the W. by two small craters. Near the N. end
are many bright little craters, many of them unrecorded. Vendelinus C is
bordered on the E. by two large semicircular formations with low walls
extending on to the floor. Mr. W.H. Maw and others have detected many
minute depressions in connection with these curious objects; and N. of
them, on the outer slope of C, where it runs out to the level of the
plateau, I have seen the surface at sunset riddled like a sieve with
craterlets and little pits. There is an irregular ring-plain N. of A,
with linear walls, and another, much smaller and brighter, on the N. of
this, standing a little beyond the N. limits of Langrenus.

LA PEYROUSE.--A much foreshortened walled-plain, 41 miles in