north america er portion of the column and in partthe scheme is provisional but in general it may be takenas expressing the progress made in the study of the geol ogy of north america up to the present time the names of the larger divisions in this scheme ofclassification or those designating the groups and systemsand the eras and periods have for the most part beenadopted from european geologists two important oneshowevernamely archean and algonkianare of ameri can birth while this scheme of classification is based on thesuccession of sedimentary beds igneous and metamorphicrock 2ajg571.jpg from america hot xxx 3gpà View Photo