Geologic formations in Glacier National Park are recognizable by dramatic exposures of Precambrian age Belt series sedimentary rock. These ancient rocks record a shallow Belt sea environment that opened and closed intermittently over many millions of years. The origin of Belt series sedimentary rocks dates from about 1,600 to 800 million years ago.
Precambrian|1,600 to 800 million years ago. Precambrian age Precambrian
Precambrian|1,600 to 800 million years ago. Precambrian age Precambrian