What makes the Old Mill Falls more unique is
the fact that in the early 1800s there was a mill that covered the
site. Through erosion and battle the mill is almost all gone.
The waterfall is primarily slate and
limestone.
What makes this waterfall unique is that there
are traces of quartz in the rocks which reflect during sunny
days.
Please read below for lesson and
quiz.
The Geological Formation of a Waterfall
Typically, a river or a stream in this case,
flows over a large step in the rocks which may have been formed by
a fault line. Over a period of years, the edges of this shelf will
gradually break away and the waterfall will steadily retreat
upstream, creating a gorge of recession. Often, the rock stratum
just below the more resistant shelf will be of a softer type,
meaning undercutting, due to splashback, will occur here to form a shallow
cave-like formation known as a rock shelter or plunge pool under
and behind the waterfall. Eventually, the outcropping, more
resistant cap rock will collapse under pressure to add blocks of
rock to the base of the waterfall. These blocks of rock are then
broken down into smaller boulders by attrition as they collide with
each other, and they also erode the base of the waterfall by
abrasion, creating a deep plunge pool.
Classification of
Waterfalls...
Block
A waterfall in a Block form occurs over a wide
breadth of the stream. The waterfall must be wider than it is tall.
A waterfall with this form does not have to be a solid sheet of
water across it's entire width.
Cascade
A waterfall of a Cascade form descends over,
gradually sloping rocks, a series of small steps in quick
succession, or a rugged sloping surface of some kind. Cascades can
be both gradual and steep.
Curtain
Curtain waterfalls occur along a wide breadth
of stream where the falls must be taller than it is wide. A
waterfall of this form often becomes narrower in low discharge
periods.
Fan
Waterfalls of a Fan form occur when the
breadth of the water in the waterfall increases during
it's decent, causing the base of
the falls to appear much wider than the top of the falls.
Horsetail
Horsetail waterfalls are characterized by the
constant or semi-constant contact the water maintains with the
bedrock as it falls. Horsetail waterfalls can be almost vertical,
as well as very gradual.
Plunge
The classic and overly cliched waterfall form, where the water drops
vertically, losing most, or all contact
with the rock face. This waterfall form has also been referred to
as a "Cataract" and a "Vertical" form waterfall.
Punchbowl
Punchbowl waterfalls, coined from the famous
Punch Bowl Falls in Oregon, occur where the stream is constricted
to a narrow breadth and is forcefully shot outward and downward
into a large pool.
Segmented
Segmented waterfalls occur where the stream is
broken into two or more channels before descending over the cliff,
causing multiple falls to occur side by side.
Slide
Similar to a cascade, a Slide type waterfall
descends a smooth, gradual bedrock surface. Slide waterfalls
maintain constant contact with the bedrock, and are often
associated with the granitic family of
bedrocks.
Tiered
Tiered waterfalls are characterized by
multiple distinct drops in relatively close succession to one
another. Whether or not a waterfall with two visible drops counts
as a tiered waterfall is up to the beholder. I typically require
tiers to be visible together and within a given distance of each
other.
The
Logging Requirements...
1) How high or tall do you estimate the
waterfall to be?
2) How wide do you estimate the waterfall to
be?
3) Using the waterfall classification guide
above, what classification of waterfall do you believe the
waterfall is?
4) Take a picture of yourself and your GPS
with the waterfall in the background and post it to the cache
page.
5) Are there any
evidence of the mill? If so what is it?
FTF Honors go to NOVASTARS
Congrats on your 1st Earthcache and being FTF on it as
well.