... lovelinesslies as much in the breadth of ideas that they embody, and in the magnitude of our struggle to interpret their anatomy, as in their elegance of form andpreservation. The animals of the Burgess Shale ... alternative, off the line. I believe that the reconstructed Burgess fauna, interpreted by the theme of replaying life'stape, offers powerful support for this different view of life: any replay of the ... eras,periods, and epochs. The boundaries of the largest divisions the eras mark the greatest events. Of the three era boundaries, two designate the mostcelebrated of mass extinctions. The late Cretaceous...