356 FKOM NEBULA TO NEBULA 



ing-up process cannot go on indefinitely without even- 

 tually causing the peaks to telescope upon themselves 

 from time to time, partly on account of their own over- 

 gorged weight, and partly because of the undermining of 

 their bases by the periodical flooding of the bottoms. This 

 telescoping process gives us the key to the terraced effect 

 so generally observed on the inner sides of the crateral 

 ramparts and supplies the reason for the otherwise sur- 

 prising precipitousness of their faces. It also explains 

 why the mountains and ramparts automatically preserve 

 a maximum uniformity of height, and why the great ring- 

 walls present their characteristic squashy, convolute ap- 

 pearance. 



MOUNTAINS. Selenographers have in the past re- 

 garded as the most puzzling of all facts about the moon 

 "the presence of the most important mountain ranges in 

 the featureless districts termed seas, where the craters 

 are fewest." By my hypothesis, the mystery becomes a 

 mystery no longer. In the oceans, when full, there could 

 not, of course, have been separate pools ; hence no craters. 

 But there were doubtless natural islands. These latter, 

 situated as they were in the very heart of the snow-pro- 

 ducing regions (these maria) accumulated the tremen- 

 dous loads, that now mark them to us as " mountains ". 



The island of Cuba is 730 miles long, the lunar Ap- 

 pennines 450 miles. Imagine rapid changes of the sea- 

 sons to occur on the earth as they do on the moon and 

 that the snows from one winter to another would keep 

 on accumulating until Cuba should be crowded with all 

 the snow it would hold, what a wonderful mountain range 

 would it not make "in the midst of a featureless plain" 

 and how like to the lunar Apennines ! As for the Val- 

 ley of the same name, that is merely the vacant trough of 

 the sound that originally separated the island from the 

 mainland. 



There would, however, be a great difference between 

 the height of the Cuban range of snow mountains and 

 the 30,000-foot Apennines, inasmuch as the surface 

 gravity here is so much greater. The latter mountains 



