The lowest water was not only very salty, but hypoxic: very low in oxygen. This was caused by the lack of water mixing. Many ordinary scavengers were absent from the lagoon floor. From the condition of the water, it follows that almost all of the fossilised animals were not living in the lagoon. They must have lived on land, in the air, or out to sea beyond the reef. Then when they died, they fell, drifted, or were washed into the lagoons from the air, ocean or land. Occasional storms at sea would have killed flying animals, and swept fish over the reef in a suspension of finely-dispersed lime. There the bodies sank into the dead zone and were preserved.