I thought it was from all the crayfish which consumed the dinosaurs in the swamps. Then again, if a meteor shower struck all the crayfish, that would explain alot,...<;^0
Can’t blame the dinos for liking crayfish... ;’)
This month, one of the science mags has a cover blurb about how mammals actually ate dinos. Dunno if that refers to scavenging the carcasses after Chicxulub, or what...