THE MOON 383 



moon's surface. Interesting replicas of the moon's crater forms 

 were thus obtained by the writer. * * * 



OVERLAP. An instance in which a larger crater overlaps and 

 partially obliterates an earlier and smaller formation is shown 

 in Maurolycus, in the roughest portion of the moon. The ob- 

 served fact that there are comparatively few of these examples is 

 eagerly taken by the volcanic advocates as proof positive that the 

 moon's craters are defunct volcanic formations. But the very 

 paucity of instances, far from proving the truth of the vulcanists' 

 contention, is mutely eloquent in our defense, since the probabili- 

 ties would be overwhelmingly against the survival of this species 

 of "overlap" crater. Yet this superposition of larger over smaller 

 craters is exemplified by Longomontanus, Maurolycus, Hainzel, 

 Schiller and others. 



SCULPTURE. The peculiar plateau of Wargentin and Phoc- 

 lydes are striking examples in more than one sense of some 

 tremendous lava deluge. The first-named object is a smooth, 

 nearly circular mesa 54 miles across and filled nearly to the level 

 of the lowest point of its rim with solidified lava. That War- 

 gentin does not reign alone in his unique grandeur is proclaimed 

 by the partial filling of Gassendi, Letronne and Hippalus to the 

 north; craters which experienced a community of origin with 

 Wargentin and the neighbouring depressions. 



As the result of moonlet impacts in the adjacent maria and 

 the fall of lithic dust from their conflagrations, Boscovicfi is 

 scarcely to be recognized as a crater, while Julius Caesar and 

 LeMonnier have nearly lost their characters. To the vaporization 

 of the more massive bodies the many "ghost craters" on the moon 

 owe their partial effacement, typified by Fra Mauro, Fracastorius 

 and Cassini. As Doctor See wrote concerning these dim spectres 

 Of the desolate lunar Hades: "So far as one can see, only two 

 explanations are tenable: i. The deposit of cosmical dust from 

 the heavens, and from conflagrations arising in the impact of 

 satellites. 2. The partial melting down of the walls by the 

 conflagrations which produced the maria, so that only an outline 

 of the original crater walls can be traced." 



The southern boundaries of the great Imbrian lava deluge 

 visioned forth as occurring far down the vista of the ages were 

 determined by Pitatus and Hippalus, while southwestward the 

 onslaught of the impacting planetoid's molten flood attained 

 Posidonius and eastward it lost itself in the Oceanus Procellarum. 

 By this memorable world-wide cataclysm, which at one stroke 

 wrought the Maria Imbrium, Nubium and Humorum and the 

 encricling ramparts known as the Apennine and Caucasus ranges, 

 "were introduced the features necessary to a broad classification 

 of the lunar surface." 



