Thanks Little Bill.
The paleontological strata show waves of mass extinction, some global. Massive taxa-wide dieoffs had been identified even among gradualists by 1950, and more than a century earlier data purportedly supporting Biblical catastrophism included a bed of fossil skeletons of billions of fish which clearly died in agony. And obviously they didn’t drown (as I said, purportedly). Raup:
[snip] In 1984, paleontologists David Raup and Jack Sepkoski published a paper claiming that they had identified a statistical periodicity in extinction rates over the last 250 million years using various forms of time series analysis. [/snip]
http://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)#Claimed_periodicity_of_mass_extinctions
http://www.pnas.org/cgi/reprint/81/3/801.pdf