cambrian
Cam.bri.an \'kam-bre--*n\ aj [ML Cambria Wales, fr. W Cymry Welshmen] 1: WELSH 2: of, relating to, or being the earliest geologic period of the Paleozoic era or the corresponding system of rocks marked by fossils of every great animal type except the vertebrate and scarcely recognizable plant fossils - Cambrian n