The available fossil record of terrestrial animals and plants documenting terminal Cretaceous extinctions is much smaller than that recording changes in the marine biota. Lack of precise resolution in methods of temporal correlation prohibits direct testing of hypotheses that extinctions in marine and terrestrial environments were globally contemporaneous on a biologically significant time scale graduated in months or years. Some evidence suggests they were not. Complex patterns of extinction and survival among terrestrial vertebrates, different geologically short-term patterns of extinction of animals in adjacent flood plain and river valley environments, apparent asynchrony of extinctions of terrestrial animals and plants, and global patterns of floral change all argue against a single, catastrophic causal factor. Terminal Cretaceous extinctions within the terrestrial biota appear to have occurred over a geologically short but biologically lengthy period and to be the results of multiple, interrelated changes in physical and biological factors.