The Probert Encyclopaedia of Rocks & Minerals

ALGONKIAN

In geology, the term Algonkian describes a period or era recognized by the United States Geological Survey and some other authorities, between the Achaean and the Palaeozoic, from both of which it is generally separated in the record by unconformities. Algonkian rocks are both sedimentary and igneous. Although fossils are rare, life certainly existed in this period.
Research Algonkian