Cambrian
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The Cambrian is the first geological period of the Paleozoic Era and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma to the beginni
Ediacaran–Cambrian boundary section at Fortune Head, Newfoundland, GSSP
Diorama of the Burgess Shale Biota
Archeocyathids from the Poleta formation in the Death Valley area
Stromatolites of the Pika Formation (Middle Cambrian) near Helen Lake, Banff National Park, Canada
Sponge
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Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera. They are sessile filter feeders that are bound to the seabed, and are one of the most ancient members of macrob
A stove-pipe sponge
Spongia officinalis, "the kitchen sponge", is dark grey when alive.
Euplectella aspergillum, a glass sponge known as "Venus's flower basket"