The Collaborative International Dictionary of English v.0.48:

Bufonite \Bu"fon*ite\, n. [L. bufo toad: cf. F. bufonite.]
   (Paleon.)
   An old name for a fossil consisting of the petrified teeth
   and palatal bones of fishes belonging to the family of
   Pycnodonts (thick teeth), whose remains occur in the
   o["o]lite and chalk formations; toadstone; -- so named from a
   notion that it was originally formed in the head of a toad.
   [1913 Webster]