terior, which is only depressed some 500 or
600 feet below the Mare, the highest peak (about 7000 feet) being on the
S.E. The walls are terraced, and include much detail, both within and
without. The most noteworthy features in connection with this formation
are the crater-cones, craterlets, pits, white spots, and light streaks
which figure on the otherwise smooth interior. Mr. T.P. Gray, F.R.A.S.,
of Bedford, who, with praiseworthy assiduity, has devoted more than ten
years to the close scrutiny of these features, Mr. Stanley Williams, and
others, have detected four crater-cones on the E. half of the floor, and
about fifty minute craters and white spots, also probably volcanic vents,
and a very curious and interesting series of light streaks, mostly
traversing the formation from E. to W. A little E. of the centre is a
dusky oval area about 6 miles across, and S.W. of this is another, much
smaller. Under some conditions of illumination the two principal light
markings may be traced over the W. wall, and for some distance on the
plain beyond.

On the southern side of Archimedes is a very rugged mountain region,
extending for more than 100 miles towards the south: on the W. of this
originates a remarkable rill-system, best seen under evening
illumination. The two principal clefts follow a nearly parallel course up
to the face of the Apennines near Mount Bradley, crossing in their way,
almost at right angles, other clefts which run at no great distance from
the E. foot of this range and ramify among the outlying hills. Archimedes
A is a brilliant little ring-plain on the S.E. of Archimedes. It casts an
extraordinary shadow at sunrise, and has a well-marked crater-row on the
E. of it, and two long narrow valleys, one of which appears to be a
southerly extension of the row.

BEER.--A very bright little crater, with an unnamed formation of about
the same size adjoining it on the N., with which is associated a curious
winding ridge that appears to traverse a gap in its N. wall.

TIMOCHARIS.--A fine ring-plain, 23 miles in diameter (the centre of a
minor ray-system). It stands isolated on the Mare Imbrium (below the
level of which it is depressed some 3000 feet), about midway between
Archimedes and Lambert. Its walls, rising about 7000 feet above the
floor, are conspicuously terraced, and on their W. outer slopes exhibit
some remarkable depressions. There is a distinct break on the N., and a
bright little crater on the N.W.,