Source : Webster's Revised Unabridged Dictionary (1913)

Chaldron \Chal"dron\, n. [OF. chaldron, F. chaudron kettle. The
   same word as caldron.]
   An English dry measure, being, at London, 36 bushels heaped
   up, or its equivalent weight, and more than twice as much at
   Newcastle. Now used exclusively for coal and coke.

   Note: In the United States the chaldron is ordinarily 2,940
         lbs, but at New York it is 2,500 lbs. --De Colange.

Source : WordNet®

chaldron
     n : a British imperial capacity measure (liquid or dry) equal to
         36 bushels