A Natural Resource Management Guide for the County of Morris A ...

This depositional till (mixture of sand, silt, clay, and boulders), created a hummocky topography with stony
low-relief ridges. The terminal moraine, a prominent feature in Morris County travels in an almost continuous
curved band, about one mile wide, from west of Dover to the Jersey City Reservoir and south to Madison
(Figure 2). It bears tremendous water supply significance to the County by its close association with the
adjacent Buried Valley Aquifer.
Glacial deposition also had a dramatic effect on surface water bodies and drainage patterns. Temporary
glacial lakes such as, Succasunna, Denville, Dover, Wharton and Passaic, the largest, were formed when
Figure 3 - Glacial Lakes in Morris County
drainage gaps were blocked by ice (Figure 3). As fine clay and silt sediments collected on the bottoms of these
draining glacial lakes, creating nearly impervious layers, the stage was set for future swamp, bog, and
wetlands development. Today's Great Swamp, Bog and Vly Meadow, Troy Meadows, and Great Piece
Meadows are all remnants of glacial Lake Passaic. The lake bottom sediments underlying the Great Swamp
are more than 50 feet deep.
The distribution of lakes in the county also show the influence of glaciation. Most naturally occurring lakes
are found north of the terminal moraine, formed in kettle holes and bogs created by the retreat of the glacier,
and by deposits of till that blocked pre-glacial drainage, or lakes scoured into bedrock. Glacially derived
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Topography and Landforms