Black chalk, a mineral of a bluish color, of a slaty texture, and soiling the fingers when handled; a variety of argillaceous slate. -- By a long chalk, by a long way; by many degrees. [Slang] Lowell. -- Chalk drawing (Fine Arts), a drawing made with crayons. See Crayon. -- Chalk formation. See Cretaceous formation, under Cretaceous. -- Chalk line, a cord rubbed with chalk, used for making straight lines on boards or other material, as a guide in cutting or in arranging work. -- Chalk mixture, a preparation of chalk, cinnamon, and sugar in gum water, much used in diarrheal affection, esp. of infants. -- Chalk period. (Geol.) See Cretaceous period, under Cretaceous. - - Chalk pit, a pit in which chalk is dug. -- Drawing chalk. See Crayon, n., 1. -- French chalk, steatite or soapstone, a soft magnesian mineral. -- Red chalk, an indurated clayey ocher containing iron, and used by painters and artificers; reddle.

Let a bleak paleness chalk the door.
Herbert.

To chalk out, to sketch with, or as with, chalk; to outline; to indicate; to plan. [Colloq.] "I shall pursue the plan I have chalked out." Burke.