Cambrian
131Paleozoic Era — or Palaeozoic Era Major interval of geologic time, с 543–248 million years ago. From the Greek for ancient life, it is the first era of the Phanerozoic Eon and is followed by the Mesozoic Era. It is divided into six periods: (from oldest to… …
132lamp shells — ▪ animal Introduction also called brachiopod, any member of the phylum Brachiopoda, a group of bottom dwelling marine invertebrates. They are covered by two valves, or shells; one valve covers the dorsal, or top, side; the other covers… …
