In the Shell People's cave Tumak wakes up and finds it deserted so has time to admire all the technological aspects of the tribe before joining them outside. After a bit of spear envy with Ahot, who obviously fancies Loana, and some "comedy" spear fishing in the pool they are attacked by an Allosaurus. Harryhausen's fight scene here is one of his greatest and ranks with the dinosaur roping in Valley of Gwangi and the skeleton fight in Jason and the Argonauts for animation skill.
After the fight Tumak gets into an argument with Ahot over his spear (he obviously suffers from spear envy)and is banished. Loana goes with him and Ahot sportingly gives Tumak his spear (the symbolism of this may be deliberate or not!). Armed with this high-tech piece of weaponry Tumak and Loana head into the wasteland again.
After this Loana tries to integrate with the Rock people and even teaches them to go swimming. We have our first view of Raquel in a wet fur bikini (she stayed dry in the earlier sea side scene) but it isn't any more revealing than when she is dry, although she does look nice shiny and wet.
Unfortunately, this idyll is interuppted by a Pterandon who grabs Loana and takes her off to it's nest as a nice snack for its chicks.
Tumak sets off in pursuit and fortunately the Pteranadon releases Loana when it is attacked by another pterosaur.
Tumak thinks she has been eaten by the pterosaur and so misses her lying on the beach.
She staggers back to the Shell people and gets them to help her look for Tumak. Its not long before they meet up again. A Rock People man has left Sakana's group and warns Tumak that they are about to attack his father's cave. Tumak and the Shell People arrive just as the attach starts and there is a big fight between the three factions. Loana gets grabbed by Sakana and Tumak fights to rescue her. He has just got Sakana at his mercy when the volcano, which has been simmering away for the whole picture, finally blows it's top. In the ensuing confusion Sakana grabs Loana once more and makes a run for it. Earthquakes and rock falls make mincemat of most of the cast and Sakana gets what he deserves (no, not Raquel).
The survivors emerge from the rubble (surprisingly close to the sea considering how long it took Tumak to get there earlier in the film). Tumak leads the survivors into the landscape no doubt thinking that he better start working on producing new tribal members with Loana right away.
And why not?