THE MOON IN MASQUERADE 115 



On the other hand, many craters, while bearing the 

 same general characteristics, are quite shallow, and 

 between the two extremes exist many hundreds of all 

 sorts and gradations. In horizontal diameter too they 

 vary amazingly. The crater Shickard, for example, is 

 120 miles across, and a dozen or more others exceed 30 

 miles. From these dimensions there is a downward 

 gradation to the limit of the telescopic power, and we 

 know not how far beyond. Again, some craters are 

 contiguous and overlap, as though one had formed later 

 and disturbed the regularity of the outlines of the 

 earlier OIK*. And, -finally, a large percentage of the 

 more conspicuous craters have within their walled plains 

 compact groups of cone-shaped hills, which attain in 

 some instances heights of several thousand feet, but 

 ncrcr r/.sr xo Jrifjh .s the ciH'ircliiuj rampartx, which 

 sometimes reach the imposing altitude of nearly 4 miles. 



2. MOUNTAINS. These appear in various forms, 

 isolated, in groups, and in ranges, and I shall take the 

 liberty of quoting a description of them from a well- 

 known authority :* 



"In turning our attention to these fea- 

 tures (mountain ranges, peaks, and hill- 

 chains), we are at the outset struck Avith the 

 paucity on the lunar surface of extensive moun- 

 tain systems as compared with its richness in 

 respect of crateral formations, and a field of 

 speculation is opened by the recognition of 

 the remarkable contrast which the moon 

 thus presents to the earth, where mountain 

 ranges are the rule and craters like the lunar 

 ones are decidedly exceptional. Another con- 

 spicuous but inexplicable fact is that the most 

 important ranges upon the moon occur in the 



*The Moon. Nasmyth and Carpenter, Chap. X. 



