Now that I see your first paragaphs...I recall a scifi story from forty or fifty years ago dealing with a crashed rocket on an earthlike-but-mostly-underwater planet where the (temporarily) surviving crew take their own DNA and make a new race of tiny underwater dwellers in their own image, and some metal plates of information that over time become Scripture, and over more time some enterprising descendants find a way to break through the surface tension (could it have been titled that? "Surface Tension"? James Blish? I don't recall) and verify the previously heretical notion that there really _is_ a world above the "sky"...

Does this sound at all familiar to anyone else?

Addendum: Oh my. Sometimes I even impress myself. And the Web is an amazing instrument. Here it is, all written. 1952:
http://users.ev1.net/~holliser/Prescience/Text/Surface.html