Many fossils from this period are preserved in Nevada's Bonanza King formation. The breakup of a supercontinent referred to as Pannotia or Rodinia and the Ediacaran extinction preceded this period. (15[1])Fossils of arthropods like the five-eyed Opabinia and the lobopod Hallucigenia (15[1])from this period were discovered by Charles Walcott in the (*) Burgess Shale. In a thesis on an animal from this period, punctuated equilibrium was proposed by Eldredge and Gould. The appearance of trilobites determines the third (10[1])stage of this period, (10[1])during which the first chordates, and many other animal phyla, first originated. For 10 points, name this geologic period during which biodiversity rapidly increased in its namesake “explosion.” ■END■