In some interpretations, it is known as “Miriam’s Well” because the second instance of Israel needing water takes place right after Miriam dies (Numbers 20:2). Interpreters may have thought that the original rock followed Israel because of Miriam but then ceased working after her death (James L. Kugel, Traditions of the Bible [Cambridge, MA: Harvard Univ. Press, 1998], p. 621).