The fusulinids in the Upper Paleozoic, however, are an anomaly. Some species of fusulinids grew to volumes of more than 100 m3 (Ross 1979). Foraminifers which grew that large today have symbiotic photosynthetic algae living in their tests, and so must live within tens of meters of the ocean surface where sunlight is available. Large foraminifers from other groups live in shallow water tropical environments today; therefore, the fusulinids are interpreted also to have lived in a similar environment (Ross 1979), yet we do not find them at the top of the geologic column. Possibly they grew at the surface of pre-flood bodies of water of low altitude (Figure 1).
Planktonic foraminifers are not found in Paleozoic or Lower Mesozoic deposits. Even though living planktonic foraminifers float and would not be expected to be found in the early flood deposits, tests of those which had died before the flood should have been on the sea floor and should have been buried with those living there. Either they were not present in those ecologic zones, or they were not preserved as fossils. Because they have thinner, more porous tests than benthic forms, they could easily have been dissolved preferentially on the sea floor before the onset of catastrophic flooding, if their shells sank below the CCD.
Benthic hyaline calcareous foraminifers become abundant in the Mesozoic. Triassic and Jurassic foraminifers are generally not as well preserved as later forms. In Cretaceous strata, both benthic and planktonic forms are diverse and abundant, making it correlative with the upper bathyal zone of the ocean today.
Foraminifers older than the Cretaceous are generally widely distributed. A Triassic species may be found in both Australia and Idaho, but nowhere in between (Tosk and Andersson 1988). Cretaceous and younger foraminifers have distribution patterns correlative with modern assemblages (Sliter 1972). Under the prevailing paradigm, this would mean that the pre-Cretaceous seas were more cosmopolitan because modern hydrographic patterns and ecologic distributions had not yet developed. Continental fragmentation and sea-floor spreading during the Cretaceous are used to account for the development of modern oceanic patterns at that time.
In a flood model, however, this pattern is what would be expected. During the more violent stages of the flood events, foraminifers from a small area would be scattered widely over the earth. As the violence of the flood died down, foraminifers would not be transported as far and might even begin developing their own ecologic distribution patterns. Major deposition during and after the Cretaceous could have become localized in basins and at continental margins. Life for foraminifers may have returned to normal in less affected areas.