RHEITA.--A formation, about 35 miles in diameter, S. of Reichenbach, with regular lofty walls, rising at a peak on the N.E. to a height of more than 14,000 feet above the interior, on which there is a small but prominent central mountain, a smaller elevation W. of the centre, and two adjoining craters at the foot of the S. wall. On the E. originates another fine valley, very similar to that already mentioned in connection with Reichenbach. It runs in a S.S.W. direction, is about 100 miles in length, and, in its widest part, is about 12 miles across. Like the Reichenbach valley, it terminates at a small crater-like object, which has a border broken down on the side facing the valley, and a small central hill. About midway between its extremities, this great gorge is crossed by a wall of rock, like a narrow bridge. JANSSEN.--An immense irregular enclosure, reminding one of the very similar area, bordered by Walter, Lexell, Hell, &c., in the third quadrant. It extends about 150 miles from E. to W., and more than 100 from N. to S., its limits on the N. being rather indefinite. Its very rugged humpy surface includes one great central mountain, and innumerable minor hills and ridges, craters, and crater-pits; but the principal feature is the magnificent curved rill-valley running from the S. side of Fabricius across the rough expanse to the S. side. This fine object, very coarse on the N., passes the central mountain on the E. side, and becomes gradually narrower as it approaches the border; before reaching which, another finer cleft branches from it on the W., and also runs to the S. side of the plain. LOCKYER.--A prominent deep ring-plain, 32 miles in diameter, with massive bright lofty walls, standing just outside the S.E. border of Janssen. Schmidt shows a minute crater on the S. rim. I have seen a crater within, at the inner foot of the W. wall, and a central peak. FABRICIUS.--A ring-plain, 55 miles in diameter, with a lofty terraced border, rising on the S.W. to a height of nearly 10,000 feet above the interior. It is partially included by the rampart of Janssen, and the great rill-valley on the floor of the latter appears to cut through its S. wall. There is a long central mountain on the floor, with a prominent ridge extending along the E. side of it. W. of Fabricius (between it and the border of Janssen) lies a very irregular enclosure, with three distinct craters within it; and on the E., running from the wall to the E. side of Janssen, is a straight narrow valley. Both Fabricius and Janssen should be viewed under a low morning sun. STEINHEIL.--A double ring-plain, W. of Janssen, 27 miles in diameter. The more easterly formation sinks to a depth of nearly 12,000 feet below the summit of the border.