THE TEN THOUSAND ISLANDS 69 



diflfer fundamentally on many vital points, such 

 as the duration of certain tribes, the time of their 

 appearance and disappearance, and on many 

 details concerning their lives. 



Let us suppose that by some terrible catastrophe 

 the entire population of the United States should 

 be destroyed and the whole country left unin- 

 habited for ages. Then, say, ten thousand years 

 after this devastation some wandering archae- 

 ologist should visit what was formerly Dade 

 County, Florida. There would not be even the 

 proverbial ' ' two streaks of rust and a right of way " 

 left of any railroad. In a hundred years all the 

 ties, bridges, and wood of any kind wovild be 

 crumbled into dust, and in a few centuries at most 

 all the metal would be rusted out and scattered 

 by the elements; the low cuts and embankments 

 would be quite obliterated by rain and wind 

 action. Down on the Key extension some remains 

 of the concrete arches might be left and they 

 would probably be taken for the ruins of an old 

 aqueduct which had supplied water to some long 

 lost city. Of Miami, the "concrete city," there 

 would probably remain a few fragments of walls 

 which hdd not yet been overthrown by time and 



