The earliest research on CAMBRIAN originated from a CAMBRIAN mountain range in Wales, England. The English name of Cambrian Mountain is Cambrian. Its prefix is C, and Carboniferous English also begins with C, in order to distinguish it from Carboniferous symbols. So draw a horizontal line in the middle of C to show the difference. Its pronunciation is close to "Cam".

Introduction:

Cambrian is the beginning of Phanerozoic, about 542 million years ago-485 million years ago. The former is Neoproterozoic Ediacaran and the latter is Ordovician.

Traditionally, it is divided into three periods: Early Cambrian (541-5130,000 years ago), Middle Cambrian (501300 million years ago) and Late Cambrian (500-490 million years ago). After 2005, the International Stratigraphic Committee divided the Lower Cambrian, changed the Cambrian (that is, strata formed during the Cambrian period) from three to four, and further revised the initial age.