The word natural has been overused for decades of marketing history. Also, just as our biological systems are strongest when the level of diversity within are highest, so are our buildings. A healthy dwelling contains a balance of material, both geological and biological. Layers of rock may rise from a simple but precise rubble-trench foundation. Added to that could be walls of cob, an echo from a time in the Old World when earthen building was the norm, not the exception.
Cob is lumps, or rounded masses of earth mixed with sand and straw, by hand and foot.
You will see people dancing on top of cob to mix it together. Smiles, sweat, and the absence of power tools will be the most striking feature. A building site that uses cob will be noticed immediately for its quietude. Then, perhaps for expediency as well as extra insulation, the north wall of the structure might be stacked straw bales with bamboo uprights stabilizing the stacks, and strong hemp twine tying the uprights together. Release from the corporate tyranny of cement may not seem like much to some people, but to me it was a great realization.