e, irregular, and very dark
marking. On the N., lies an immense bright plain, extending nearly to the
border of Endymion.

WEST LONGITUDE 60 deg. TO 40 deg.

TARUNTIUS.--Notwithstanding its comparatively low walls, this ring-plain,
44 miles in diameter, is a very conspicuous object under a rising sun.
Like Vitello and a few other formations, it has an inner ring on the
floor, concentric with the outer rampart, which I have often seen nearly
complete under evening illumination. There is a small bright crater on
the S.E. wall, and a larger one on the crest of the N.E. wall, with a
much more minute depression on the W. of it, the intervening space
exhibiting signs of disturbance. The upper portion of the wall is very
steep, contrasting in this respect with the very gentle inclination of
the _glacis_, which on the S. extends to a distance of at least 30 miles
before it sinks to the level of the surrounding country, the gradient
probably being as slight as 1 in 45. Two low dusky rings and a long
narrow valley with brilliant flanks are prominent objects on the plain E.
of Taruntius under a low evening sun.

SECCHI.--A partially enclosed little ring-plain S. of Taruntius, with a
prominent central mountain and bright walls. There is a short cleft
running in a N.E. direction from a point near the E. wall. Schmidt
represents it as a row of inosculating craters.

PICARD.--The largest of the craters on the surface of the Mare Crisium,
21 miles in diameter. The floor, which includes a central mountain, is
depressed about 2000 feet below the outer surface, and is surrounded by
walls rising some 3000 feet above the Mare. A small but lofty ring-plain,
Picard E, on the E., near the border of the Mare, is remarkable for its
change of aspect under different angles of illumination. A long curved
ridge running S. from this, with a lower ridge on the west, sometimes
resemble a large enclosure with a central mountain. Still farther S.,
there is another bright deep crater, _a_, with a large low ring adjoining
it on the S., abutting on the S.E. border of the Mare. Schroter bestowed
much attention on these and other formations on the Mare Crisium, and
attributed certain changes which he observed to a lunar atmosphere.

PEIRCE.--This formation, smaller than Picard, is also prominent, its
border being very bright. There is a central peak, which, though not an
easy object, I once glimpsed with a 4 inch Cook achromatic, and have seen
it two