calcareous tufa

Its bed is composed of calcareous tufa, chiefly the remains of reeds and mosses, forming a beautiful succession of cascades.

The exterior was entirely of calcareous tufa of Tivoli, called travertine, a fine hard and white stone.

The formation is soft calcareous tufa, such as forms the bottom of all this basin.

Large patches of these flats are covered with white calcareous tufa resting on perfectly horizontal strata of trap.

The fossil bones which lie in the calcareous tufa of this region will yet, we hope, reveal the ancient fauna.