The Precambrian in Michigan, US

Paleontology and geology

Some of the oldest rocks in North America are exposed in Michigan’s Upper Peninsula. These metamorphic and igneous rocks are the remnants of mountain ranges raised during the Precambrian collision of landmasses that formed the beginnings of the North American continent. Partially metamorphosed sedimentary rocks from 2.1 billion years ago contain fossil evidence of the earliest eukaryotes (organisms whose cells have a nucleus), a filamentous alga called Grypania spiralis.