Examples from the Web for proterozoic
Similar forms are abundant in late Proterozoic strata of Montana.
In regard to abundance of fossil animals the oldest (Cambrian) Paleozoic strata stand out in marked contrast to the Proterozoic.
The later Proterozoic strata have been much less deformed and in many cases they are practically unaltered.
Hence, uplift alone cannot account for extensive glaciation in subtropical latitudes during the Permian and Proterozoic.Climatic Changes|Ellsworth Huntington
This second series of rocks is called the Proterozoic (beginning of life) series, and marks a long age in the worlds history.The Outline of History: Being a Plain History of Life and Mankind|Herbert George Wells