Chemistry and the missing era of evolution

The Darwinian evolution of life on earth depends utterly on complex molecular machinery, which, it seems, could only have arisen through a Darwinian evolution. The "RNA world" idea reduces this paradox, but requires a geochemically implausible supply of RNA monomers. A pre-RNA era of natural selection is implied. I suggest that originally this was based on inorganic materials that came to replicate permutations with specific (e.g. catalytic) effects.