Encara no tenim significats per a "porous tufa".
1The vast deposits of porous tufa in the surrounding country are certainly evidences of former great eruptions from Mount Taal.
2The rock is partly calcareous, and partly of a porous tufa, but softer than that which I saw in the Houle.
3From hence we passed between the Tel Shiehhan and Tel Es- Szoub; the ground is here covered with heaps of porous tufa and pumice stone.
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