A deposit of wash-dirt lying over bedrock.
Mid 19th century; earliest use found in Robert Brough Smyth (1830–1889), civil servant and mining engineer.
英语词典包含464360条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。