GRUITHUISEN.—­This ring-plain, 10 miles in diameter, is situated on the Mare Imbrium on the N.E. of Delisle.  It is associated with a number of ridges trending towards the region N. of Aristarchus and Herodotus.

THE LAPLACE PROMONTORY.—­A magnificent headland marking the extreme western extremity of the finest bay on the moon’s visible surface, the Sinus Iridum; above which it towers to a height of 9000 feet or more, projecting considerably in front of the line of massive cliffs which define the border of the Sinus, and presenting a long straight face to the S.E.  Near its summit are two large but shallow depressions, the more easterly having a very bright interior.  At a lower level, almost directly below the last, is a third depression.  All three are easy objects under a low sun.  The best view of the promontory and its surroundings is obtained when the E. side of the bay is on the morning terminator.  Its prominent shadow is traceable for many days after sunrise.

THE HERACLIDES PROMONTORY.—­The less lofty but still very imposing headland at the E. end of the Sinus Iridum, rising more than 4000 feet above it.  It consists of a number of distinct mountains, forming a triangular-shaped group running out to a point at the S.W. extremity of the bay, and projecting considerably beyond the shore-line.  There is a considerable crater on the E. side of the headland, not visible till a late stage of sunrise.  It is among the mountains composing this promontory that some ingenuity and imagination have been expended in endeavouring to trace the lineaments of a female face, termed the “Moon-maiden.”

BIANCHINI.—­A fine ring-plain, about 18 miles in diameter, on the N.E. side of the Sinus Iridum, surrounded by the lofty mountains defining the border of the bay.  Its walls, which are prominently terraced within, rise about 7000 feet on the E., and about 8000 feet on the W. above the floor, which includes a prominent ridge and a conspicuous central mountain.  There is a distinct crater on the S. wall, not shown in the maps.  Between this side of the formation and the bay is a number of hills running parallel to the shore-line:  these, with the intervening valleys, will repay examination at sunrise.

MAUPERTUIS.—­A great mountain enclosure of irregular shape, about 20 miles in diameter, in the midst of the Sinus Iridum highlands, N. of Laplace.  The walls are much broken by passes, and the interior includes many hills and ridges.

CONDAMINE.—­A rhomboidal-shaped ring-plain, about 23 miles in diameter, N. of Maupertuis, with lofty walls, especially on the E., where they rise some 4000 feet above the interior.  There are three large depressions on the outer N.W. slope, and at least three minute craters on the crest of the wall just above.  Though neither Neison nor Schmidt draw any detail thereon, there is a prominent ridge on the N. side of the floor, and a low circular hill on the S. On the S.E. four long ridges or spurs radiate from the wall, and on the N.E. are three remarkable square-shaped enclosures.  On the edge of the Mare Frigoris, N.W. of Condamine, are many little craters with bright rims and a distinct short cleft, running parallel to the coast-line.  The winding valleys in the region bordering the Sinus Iridum, and other curious details, render this portion of the moon’s surface almost unique.