Chapter Four begins with a massive tidal wave caused by heavy rain sweeping over the waterfall and swamping the lake; the black pterosaurs den is destroyed by this wave, with only one of them managing to escape before the wave hits. Down in the forest the Allosaurus and a small group of sauropods he was stalking try to escape the flood but are swept away. The sauropods the Allosaurus was hunting survive the waters, but dozens more drown; the Ceratosaurus pack gorges itself on the carcasses. The pack separates, and the Allosaurus sees his opportunity. Diving underwater, it manages to use the corpses of the sauropods as cover to ambush, kill and devour one of the Ceratosaurs.