Galena Moraine Biological Reserve

The Galena Moraine Biological Reserve is situated on the Valparaiso Moraine which is a terminal moraine forming a U around the southern end of Lake Michigan.  The Valparaiso Moraine formed during the Crown Point Phase of the Wisconsin glaciation approximately 15,200 years ago. "By this time the Lake Michigan lobe of the glacier was thin enough that as it grew it was restrained by the regional topography. Thus the lobe was relatively confined to the width of the Lake Michigan basin.  At the beginning of the Crown Point phase, the curved southern edge of the Lake Michigan lobe of the glacier extended from eastern Wisconsin, through northeast Illinois, northwest Indiana, to western Michigan.  Huge amounts of sediment from this lobe were piled up along its edge into long curved ridges and hills know as the Valparaiso Moraine."  (Schoon, Calumet Beginnings: Ancient Shorelines and Settlements at the South End of Lake Michigan, 2003).

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The moraine at GMBR is composed of medium to course sand intermingled with glacial erratics (mostly granite in composition) and ranging in size from small stones to large boulders 6 feet in diameter.