“As you always choose the most picturesque theories to rest your belief upon, I shall not complain if you accept the lunar volcano theory of meteorites,” I replied. “But, for the present, we have done with it, and I am now going to ask you to inspect the photograph for other interesting objects. East and north of the great ring you will see an extensive mass of mountains. Those on the north, with immense buttresses projecting into the _Mare Imbrium_, are the lunar Carpathians. I have already directed your attention to a comparatively small crater ring which resembles a reduced copy of Copernicus, situated in these mountains at the head of a bay which penetrates southward between high ridges, for about 30 miles. This crater is named Gay Lussac. It has a small deep neighbor on the southwest. West of Gay Lussac the Carpathians gradually dwindle away until they sink to the level of the plain. Toward the east they project in several bold headlands, terminating with towering peaks into the ‘sea.’ Lying off the point of the headland on the western side of the bay that leads to Gay Lussac you will perceive two charming little craters, almost perfect twins. Much farther toward the north and west is a larger crater, more than half of whose interior is black with shadow. This is Pytheas. Its lonely situation is very striking, but upon close inspection you will notice that a low range of hills appears to connect it with the twin craters that I have just pointed out. This range of hills, lying on the ‘sea’ bottom, is curiously forked, the other branch leading to a pair of small peaks in the ‘sea,’ which possess no craters. The little crater east of Pytheas is also a beautiful object in the picture. “Near the eastern end of the Carpathians the mountains make their greatest advance into the _Mare Imbrium_, leaving a large square-cornered bay on the west. From this point they turn southward, forming a complicated mass of peaks and ridges interspersed with craters and pits. These mountains east of Copernicus are among the most singular upon the moon, for they inclose a group of irregular-shaped plains, the walls of which consist of immense, more or less separate, masses. Look at the one nearest to Copernicus, which has somewhat the form of a starfish, and observe how curiously its southern border reflects, on a smaller scale, the forms characteristic of the headlands and bays along the shore of the _Mare Imbrium_ below.