The Collaborative International Dictionary of English v.0.48:

Paleozoology \Pa`le*o*zo*["o]l"o*gy\
   (p[=a]`l[-e]*[-o]*z[-o]*[o^]l"[-o]*j[y^]), n. [Paleo- +
   Zoology.]
   The science of extinct animals, a branch of paleontology.
   [1913 Webster] Palesie

WordNet (r) 3.0 (2006):

paleozoology
    n 1: the study of fossil animals [syn: paleozoology,
         palaeozoology]