Tarzan the Terrible (Ballantine Tarzan, U2008)

Second Ballantine printing; Eighth in the timeless series. Lieutenant Obergatz had fled in terror from the vengeance of Tarzan of the Apes, taking with him the ape-man's beloved mate, Jane. Now Tarzan was following the faint spoor of their flight into a region no modern man had ever penetrated. The trail led across seemingly impassable marshes into Pal-ul-don, a savage land where primitve Waz-don and Ho-don fought fiercely, wielding knives with their long prehensile tails, and where huge Triceratops still survived from the dim dawn of time.