Evbxp: Volcanic breccia—Dacitic to andesitic lithic tuff breccia with lesser (crystal) lithic lapilli tuff and minor agglomerate; typically dark green-gray to light gray, with multicolored red, green, and gray to black volcanic clasts; weathers gray-brown; moderately to poorly sorted; very thick to massive.
Witches Abroad (Wikipedia) Witches Abroad is the twelfth Discworld novel by Terry Pratchett, originally published in 1991.