Also 8 traas, traass. [a. Du. tras, Ger. trasz, earlier terra·s, tira·s.] = TARRAS.
[1793. Smeaton, Edystone L., § 201. Tarras. [Note] This substance, when prepared for use, is by the Dutch called Tras, from which our appellation of Tarras undoubtedly originates.]
1796. Kirwan, Elem. Min. (ed. 2), I. 354. Often mistaken for volcanic traass.
1811. Pinkerton, Petralogy, II. 427. The trass of the environs of Andernach, on the left bank of the Rhine, is a kind of puzzolana formed of small fragments of pumice, and several species of lavas…. Trass is transported by water as far as Dort, to be reduced to powder in stamping mills worked by the wind…. The Dutch also supply England with trass.
1838. Civil Eng. & Arch. Jrnl., I. 412/2. Tarras, or trass, is a bluish black cellular trap or lava, quarried at Andernach on the Rhine, into millstones.
1862. G. P. Scrope, Volcanos (ed. 2), 178. Both puzzolana and trass, when mixed up with lime, set readily under water.
