Rocks Contain Impressions of Irreversible Events

Historical chronology, human or geological, depends... upon comparable impersonal principles. If one scribes with a stylus on a plate of wet clay two marks, the second crossing the first, another person on examining these marks can tell unambiguously which was made first and which second, because the latter event irreversibly disturbs its predecessor. In virtue of the fact that most of the rocks of the earth contain imprints of a succession of such irreversible events, an unambiguous working ...

 The Skrodes

Ravna looked across the surf. When the waves backed down the sand, she could see the Skroderiders’ fronds peeping out of the spray. How she envied them; if tensions annoyed them, they could simply turn them off. The Skroderiders were one of the most common sophonts in the Beyond. There were many varieties, but analysis agreed with legend: very long ago they had been one species. Somewhere in the off-Net past, they had been sessile dwellers of sea shores. Left to themselves, they had developed...