scrutiny, as it abounds in detail and includes many short clefts. HARBINGER, MOUNTAINS.--A remarkable group of moderate height, mostly extending from the N.W. towards Aristarchus. They include a large incomplete walled-plain about 30 miles in diameter, defined on the W. by a lofty border, forming part of a mountain chain, and open to the south. This curious formation has many depressions in connection with its N.W. edge. On the N. of it there is a crater-row and a very peculiar zig-zag cleft. The region should be observed when the E. longitude of the morning terminator is about 45 deg. SCHIAPARELLI.--A conspicuous formation, about 16 miles in diameter, between Herodotus and the N.E. limb, with a border rising nearly 2000 feet above the Mare, and about 1000 more above the floor, on which Schmidt shows a central hill. WOLLASTON.--A small bright crater on the Mare N. of the Harbinger Mountains, surpassed in interest by a remarkable formation a few miles S. of it, Wollaston B, an object of about the same size, but which is associated with a much larger enclosure, resembling a walled-plain, lying on the N. side of it. This formation has a lofty border on the W., surmounted by two small craters. The wall is lower on the E. and exhibits a gap. There is a central hill, only visible under a low sun. About midway between Wollaston and this enclosure stands a small isolated triangular mountain. From a hill on the E. runs a rill valley to the more westerly of a pair of craters, connected by a ridge, on the S.E. of Wollaston B. MAIRAN.--A bright ring-plain of irregular shape, 25 miles in diameter, on the E. of the Heraclides promontory. The border, especially on the E., varies considerably in altitude, as is evident from its shadow at sunrise; at one peak on the W. it is said to attain a height of more than 15,000 feet above the interior. There is a very minute crater on the crest of the S. wall, down the inner slope of which runs a rill-like valley. About halfway down the inner face of the E. wall are two other small craters, connected together by a winding valley. These features may be seen under morning illumination, when about one-fourth of the floor is in sunlight. Schroter is the only selenographer who gives Mairan a central mountain. In this he is right. I have seen without difficulty on several occasions a low hill near the centre. The formation is surrounded by a number of conspicuous craters and crater-pits. On the N. there is a short rill-like valley, and another, much coarser, on the S. SHARP.--A ring-plain somewhat smaller than the last, on the E. of the Sinus Iridum, from the coast-line of which it is separated by lofty mountains. There is a distinct crater at the foot of its N.E. wall, and a bright central mountain on the floor. On the N. is a prominent enclosure, nearly as large as Sharp itself; and on the N.E. a brilliant little ring- plain, A, about 8 miles in diameter, connected with Sharp, as Madler shows, by a wide valley.