What are Glacial Erratics?
Glacial erratics, such as Pamachapura, are rocks transported by
glaciers and laid down a distance, often many miles, from their
original location. Many are unlike the bedrock on which they rest
because glacial ice in many places flowed across different types of
bedrock. Most show evidence of glacial erosion by their subrounded
to rounded shape, faceted sides, and striated and polished surface.
They are found through-out northern New Jersey and they record the
direction the glacier flowed.
How did this Massive Boulder get here?
Most of the glacial sediment in New Jersey, such as this glacial
erratic, was deposited during the late Wisconsinan ice age about
21,000 years ago. During this period an ice sheet advanced
southward in small lobes following the Hudson, Passaic, Hackensack,
Kittatinny, and Delaware Valleys. Over time, the glacier ice became
thick enough to flow over Kittatinny Mountain, New Jersey
Highlands, and Watchung Mountains. As the glacier ice advanced over
northern New Jersey it deposited glacial sediment. Its furthest
advance in most places is marked by the Terminal Moraine which
forms a nearly continuous low ridge from Belvidere through Perth
Amboy to New York.
Reference: New Jersey Geological Survey Information
Circular 'Glacial Sediment and the Ice Age in New Jersey'
Logging Requirements:
- Take a picture with GPS in front of the 'Stone from
Heaven'
- Estimate the volume in cubic feet of the glacial erratic using
length, width, and height
- How do you think this rock got here and what is the connection
with the towns name?
- In what year did Glen Rock take its name?
Note: All answers should be emailed to the cache
owner.