The ~ is a layer of earth that is just below the surface soil but above hard rock.
...the chalk ~ on the site.
N-UNCOUNT: also a N
The ~ is a layer of earth that is just below the surface soil but above hard rock.
...the chalk ~ on the site.
N-UNCOUNT: also a N
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012