+ Larger Font | + Smaller Font Moggy Hollow at Leonard J. Buck Garden
The Wisconsin glacier started its southern movement
about 50,000 years ago. This is a relatively short time geologically
when you consider that the red shale that underlies our area was laid
down as sediment about 185 million years ago during Triassic times.
The trap ridges, now the Watchung Mountains, boiled out of the earth
as molten lava and solidified about 175 million years ago. The Wisconsin
ice sheet reached the Paterson - Little Falls area approximately 15,000
years ago, reaching its terminal moraine, or most southern position,
about 3,000 years later. As the ice sheet melted and started to retreat
towards Paterson, its progress was much faster, taking only about 1,000
years. Lake Passaic ceased being a lake about 11,000 years ago, followed
by post-glacial lakes. Even today we have Great Piece Meadows, Hatfield
Swamp, and the Great Swamp as shallow reminders of that past glacial
era. When the Wisconsin ice sheet reached the gaps at Paterson and
Little Falls and sealed them, water in front of the ice accumulated
as a lake. The lake formed was very small and shallow since the overflow
was over a low divide. This drainage basin may have had its outlet
at Little Falls, and then through the Short Hills gap- As the glacier
continued its southern course, it closed the Short Hills gap through
the Watchung Mountains. This was the original course of the Hudson
River until erosion further north changed its course to today's location.
With the Short Hills gap closed by ice, the water before the glacier
filled the basin to a depth of approximately 160 to 200 feet until
a new outlet was reached at Moggy Hollow. As the glacier retreated,
it plugged the pre-glacial outlet at Short Hills with drift, and Moggy
Hollow remained the outlet of the lake. The lake grew in size as the
ice retreated. At its maximum Lake Passaic was about 30 miles long,
8 to 10 miles wide, 240 feet deep at maximum depth, and 160 to 200
feet deep over wide areas. When the glacier retreated north to the
Paterson - Little Falls gaps they were opened, and the lake drained
through them, thus ending the overflow through Moggy Hollow. In the
years necessary for the water to wear down the hard rocks in the gaps
to their present level, there were post-glacial lakes in the basin.
The longest-lived of these was the one that occupied the area of The
Great Swamp northwest of Long Hill, which persisted while the overflow
was cutting a narrow gorge at Millington. The elevation of this lake
at the outset was about 320 feet above sea level, but as the outlet
was slowly cut down to its present level of 221 feet, the lake was
drained. "Totem Pole Museum, November 1959". (revised, 1991) The Moggy
Hollow National Landmark is owned by the Upper Raritan Watershed Association.
It is adjacent to the Leonard J. Buck Garden in Far Hills, New Jersey. |
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