the world > the earth > structure of the earth > age or period > [adjective] > primary or Palaeozoic > Cambrian (2)
Geology. A name given by Sedgwick in 1836 to a group or ‘system’ of Palæozoic rocks lying below the Silurian, in Wales and Cumbria.
Geology. Designating the Middle Cambrian epoch in (esp. western) North America; of or relating to this epoch. Cf. Acadian, adj. 2a.