The Collaborative International Dictionary of English v.0.48:

Petrogale \Pe*trog"a*le\ (p[-e]*tr[o^]g"[.a]*l[=e]), n. [NL.,
   fr. Gr. pe`tra a rock + galh^ a weasel.] (Zool.)
   Any Australian kangaroo of the genus Petrogale, as the rock
   wallaby (Petrogale penicillata).
   [1913 Webster]