We see in many cases in the more recent tertiary formations that rarity precedes extinction; and we know that this has been the progress of events with those animals which have been exterminated, either locally or wholly, through man’s agency. I may repeat what I published in 1845 , namely, that to admit that species generally become rare before they become extinct⁠—to feel no surprise at the rarity of a species, and yet to marvel greatly when the species ceases to exist, is much the same as to admit that sickness in the individual is the forerunner of death⁠—to feel no surprise at sickness, but, when the sick man dies, to wonder and to suspect that he died by some deed of violence.