and cross the ridges just mentioned.  They follow a parallel course, and terminate on the S. side of a crater-row, consisting of three bright craters ranging in a line parallel to the coarse valley.  On the N. side of these objects, and tangential to them, is another cleft, which traverses the W. and E. walls of Lohrmann, and, crossing the region between it and Riccioli, terminates apparently at the W. wall of the latter formation.  No map shows this cleft, though it is obvious enough; and, when the E. wall of Hevel is on the morning terminator, the notches made by it in the border of Lohrmann are easily detected.  Capt.  Noble, F.R.A.S., aptly compares two of the crossed clefts to a pair of scissors, the craters at which they terminate representing the oval handles.  On the grey surface of the Mare W. of Lohrmann is the bright crater Lohrmann A, from which, running N., proceeds a rill-like valley ending at a large white spot, which has a glistening lustre under a high light.

HEVEL.—­A great walled-plain, 71 miles in diameter, adjoining Lohrmann on the N., with a broad western rampart, rising at one peak to a height above the interior of nearly 6000 feet, and presenting a steep bright face to the Oceanus Procellarum.  There are three prominent craters near its crest, and one or two breaks in its continuity.  It is not so lofty and is more broken on the E., where three conspicuous craters stand on its inner slope.  The floor is slightly convex, and includes a triangular central mountain, on which there is a small crater.  The S. half of the interior is crossed by four clefts:  (l) running from a little crater N. of the central mountain, on the W. side of it, to a hill at the foot of the S.W. wall; (2) originating near the most southerly of the three craters on the inner slope of the E. wall, and crossing 1, terminates at the foot of the W. wall; (3) has the same origin as 2, crosses 1, and, passing over a craterlet W. of the central mountain, also runs up to the W. wall at a point considerably N. of that where 2 joins the latter; (4) runs from the craterlet just mentioned to the W. end of 2.

CAVALERIUS.—­The most northerly member of the linear chain, a ring-plain, 41 miles in diameter, with terraced walls rising about 10,000 feet above the floor.  Within there is a long central mountain with three peaks.  Under a high light the region on the W. is seen to be crossed by broad light streaks.

OLBERS.—­A large ring-plain, 41 miles in diameter, near the limb, N.E. of Cavalerius.  Though a very distinct formation, it is difficult to see its details except under favourable conditions of libration.  It has a large crater on its W. wall, a smaller one on the E., and a third on the N. The floor includes a central mountain, and, according to Schmidt, four craters.  He also shows a crater-rill on the W. wall, N. of the large crater thereon.  Olbers is the origin of a fine system of light rays.

GALILEO.—­A ring-plain, about 9 miles in diameter, N.E. of Reiner, associated with ridges, some of which extend to the “Jew’s Harp” marking referred to under this formation.