Running the gauntlet of hostile tribes, the expedition finally reaches the lost world with the aid of Indian guides, who are superstitiously scared of the area. Summerlee retains his scepticism – although being delighted at making other scientific discoveries in the field of botany and entomology: even a glimpse of a pterodactyl at a distance fails to convince him, believing it is some species of stork (the sharper-eyed Roxton is inclined to agree it is not a stork but has no clue what it really is), until a night-time encounter when it flies down and is seen by all at close range, as it steals the companions' dinner. After this, Summerlee apologises to Challenger. The cliffs to the plateau itself prove to be apparently unscalable, but an adjacent pinnacle turns out to be climbable, and moreover, has a tall tree which can be cut down and used as a bridge, which allows the four explorers to cross to the plateau. However, they are almost immediately trapped on it, thanks to the treachery of one of their luggage-porters, Gomez: who, as it turns out, is a former slaver whose brother had previously been killed by Roxton during his anti-slavery activities. Gomez takes his revenge by dropping the tree off the cliff, stranding the explorers on the plateau. Gomez himself is subsequently killed by another porter, a negro ex-slave named Zambo, who remains loyal to the party: but the latter is unable to do much more to help, other than send some of the company's supplies over by rope.