Roger Weller, geology instructor
firstname.lastname@example.org copyright 2011-R.Weller
Centennial Mine, Centennial, Houghton County, Michigan
The skull shape is created when the copper is deposited around
a rounded boulder within a conglomerate. At a later time the
is weathered away, leaving just the copper.
Photo is copyright free for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College
from the A.L. Flagg collection