DAWES.—­A ring-plain 14 miles in diameter, situated N.W. of Plinius, on a nearly circular light area.  Its bright border rises to a height of 2000 feet above the Mare, and includes a central mountain, a white marking on the E., and a ridge running from the mountain to the S. wall.  There are two closely parallel clefts on the N. side of the plateau running from E. to W., that nearer Dawes being the longer, and having a craterlet standing upon it about midway between its extremities.  At its W. termination there is a crater-row running at right angles to it.  The light area appears to be bounded on the E. by a low curved bank.

VITRUVIUS.—­A ring-plain 19 miles in diameter with bright but not very lofty walls, situated among the mountains near the S.W. side of the Mare Serenitatis.  It is surrounded by a region remarkable for its great variability in brightness.  There is a large bright ring-plain on the W., with a less conspicuous companion on the S. of it.

MARALDI.—­A deep but rather inconspicuous formation, bounded on the W. by a polygonal border.  A small ring-plain with a central mountain is connected with the S.W. wall; and, running in a N. direction from this, is a short mountain arm which joins a large circular enclosure with a low broken border standing on the N. side of the Mare Tranquilitatis.

LITTROW.—­A peculiar ring-plain, rather smaller than the last, some distance N. of Vitruvius, on the rocky W. border of the Mare Serenitatis.  It is shaped like the letter D, the straight side facing the W. There is a distinct crater on the N. wall.  On the N.W. it is flanked by three irregular ring-plains, and on the S.E. by a fourth.  Neison shows two small mountains on the floor, but Schmidt, whose drawing is very true to nature, has no detail whatever.  A fine cleft may be traced from near the foot of the E. wall to Mount Argaeus, passing S. of a bright crater on the Mare E. of Littrow.  It extends towards the Plinius system, and is probably connected with it.

MOUNT ARGAEUS.—­There are few objects on the moon’s visible surface which afford a more striking and beautiful picture than this mountain and its surrounding heights with their shadows a few hours after sunrise.  It attains an altitude of more than 8000 feet above the Mare, and at a certain phase resembles a bright spear-head or dagger.  There is a well-defined rimmed depression abutting on its southern point.

ROMER.—­A prominent formation of irregular outline, 24 miles in diameter, situated in the midst of the Taurus highlands.  It has a very large central mountain, a crater on the N. side of the floor, and terraced inner slopes.  Some distance on the N. is another ring, nearly as large, with a crater on its S. rim, and between this and Posidonius is another with a wide gap on the S. and a crater on its N. border.  One of the most remarkable crater-rills on the moon runs from the E. side of Romer through this latter ring, and then northwards on to the plain W. of Posidonius.  Under suitable conditions, it can be seen as such in a 4 inch achromatic.  It is easily traceable as a rill in a photograph of the N. polar region of the moon taken by MM.  Henry at the Paris Observatory, and recently published in Knowledge.