NATURAL and CULTURAL FEATURES of MONMOUTH COUNTY

illion dollar a year horse industry; 29% of NJ’s 42,500 horses are part of the racing industry
(Sapia, 2007c).
TERRAIN
Lowlands and plains characterize most of the County, with a small isolated fragment of the Pine
Barrens along the border of Manalapan, Marlboro and Middlesex County (MCPB, 1975).
Scattered throughout the Coastal Plain are numerous shallow basins that originated during the
Wisconsinan glacial age in the Late-Pleistocene. These ‘spungs’ were formed when strong
winds blowing down the Hudson River Valley across the Laurentide ice sheet blasted the barren
terrain of central and south Jersey, eroding ‘blowouts’ in the ground. (French and Demitroff,
2001). When the glaciers melted and sea level rose, these periglacial depressions filled with
groundwater and formed bogs and ponds, some of which still remain today as (seasonally
ephemeral) vernal pools. Over the last 125 years, many of these pools have degraded or dried up
as the water table fell due to over-withdrawal and urbanization. (Demitroff, 2006; Kraft, 2001;
Lathrop et. al., 2005).
The most prominent landform in the County is an erosion-resistant ridge of glauconite and sand
formations capped by Tertiary ironstone conglomerate and yellow gravel (MCPB, 1975; USGS,
2003). The Mount Pleasant Hills extend from Keyport southwest through Imlaystown to the
Delaware Bay in Salem County, and is the drainage divide between the Inner and Outer Coastal
Plain (Kraft, 2001; MCPB, 1975). These cuesta shaped hills, which are named after what is now
known as the Freneau section of Aberdeen, also extend eastward from Keyport to the Navesink
Highlands – the hills of Atlantic Highlands, Highlands and Middletown that face Sandy Hook
Bay (a cuesta is a long ridge with a gentle slope on one side and a deep scarp face on the other)
(Aberdeen, 2005; Kraft, 2001). Mount Mitchill in the Navesink Highlands rises abruptly from
sea level to a maximum elevation of 266 feet, and is the highest point on a shoreline of the
eastern seaboard south of Maine (MCPB, 1975; USGS, 2003). During the most subarctic period
of the Wisconsinan, peaking about 21,000 years ago, the Navesink Highlands was a high
escarpment along the valley of the combined Hudson/Raritan Rivers before glacial melt drowned
the two rivers into an estuary about 6000 years ago; during the Wisconsinan, Mt. Mitchill may
have been as much as 600 feet above sea level (Smith, 2000; USGS, 2003). About 15 million
years earlier, after deposition of the Cohansey Sands and during the last great rise in sea level
from mid-Miocene to early Pliocene time, the ancestral Hudson River cut southwest across the
Coastal Plain during an uplift of the rocks in northern NJ. The Hudson turned south near
Clarksburg and arced east to discharge into the ocean near Tuckerton; it left behind the yellow
gravel of the Beacon Hill Formation, named for a 373 foot hill in Leonardo near the Atlantic
Highlands border (Dahlgren, 1977; Owens and Minard, 1979; USGS, 2003).
From the Navesink Highlands westward, the Mount Pleasant Hills range in elevation from 200
feet at Chapel Hill, Middletown, to 391 feet at Crawford Hill in Holmdel, which is the highest
point in the County (MCPB, 1975). Near Perrineville a series of hills rise to nearly 360 feet in
elevation; west of Imlaystown the relief again flattens out, as it also does west of Morganville,
and the hills only rise to 100 feet or so in elevation (MCPB, 1975). Wind scour markings on
sandblasted ironstone blocks capping the high points around Perrineville that were formed during
the Late Pleistocene (as well as the widespread presence of wind-abraded stone and cobbles
throughout South Jersey) indicate a harsh climate like that of North Greenland during the Ice
Age’s coldest periods (French and Demitroff, 2001; French et al 2003, 2005; Moore 2003). A
smaller group of hills called the Hominy Hills (formerly called Manhomony Hills) stretch from