Portage Lake Lava Series  search
BTChronostratigraphic Units
 .Precambrian
 ..Proterozoic
 ...Keweenawan
 ....Portage Lake Lava Series
RTMichigan
SNTops of conglomerate beds used for stratigraphic reference include: Saint Louis Conglomerate, The Old Colony and Wolverine sandstones, and the Kingston, Calumet and Hecla, Houghton, Allouez, Pewabic West, and Hancock conglomerates. Upper Peninsula of Mich