The Spicer Lake basin lies within the Valparaiso moraine formed during the waning stages of Wisconsinan ice sheet during its last advance in the Lake Michigan basin. The basin was probably formed when a large block of ice separated from main ice sheet and was surrounded by later morainal deposits.  The basin contains two small kettle lakes and a large central mat anchored at west end by a kettle lake and red maple-black ash-elm swamp forest. The eastern 2/3 is mainly a shrub swamp on a floating peat/sphagnum mat (> 1.1 m thick) with an open water hinge line around the edge. The basin harbors several state endangered and threatened species. The two small lakes are seasonally stratified, dystrophic, and contain benthic and plankton flora similar to more northern lakes.  The lakes are surround by a yellow pond lily and swamp loosestrife floating ring that grades into a button bush-winterberry-swamp rose-blueberry shrub zone.  Behind the shrub zone is the red maple-elm-black ash swamp forest.  The wetland is used by Canada Geese, Sandhill Cranes, Wood Ducks,  Red-shouldered Hawks, and several warbler species for nesting.  In addition many bird species use it during migration including flocks of Rusty Blackbirds. The peat in the wetland and lakes holds a record of the floristic history of the region and was recently used to examine the history of American Beech in the area.  As an Indiana state-dedicated nature preserve, it is recognized by the Indiana DNR as a site worthy of protection. (IDNR Nature Preserves listings by county.) It is owned and managed by St. Joseph County Parks. A quarter-mile boardwalk, two additional viewing platforms and roughly 7 miles of trails exist within the property and make this wetland accessible to hikers, wildlife watchers and nature photographers.