Skip to content

Fall Line at Holmesburg Dam EarthCache

Hidden : 4/28/2008
Difficulty:
1.5 out of 5
Terrain:
2 out of 5

Size: Size:   not chosen (not chosen)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:

Beautiful PennyPack Park of the Fairmount Park Commission. This little river offers tons of history and knowledge for our great city!

Holmesburg is one of the older communities of Philadelphia and home to the nations oldest stone-arch bridge still carrying the traffic of a major highway. But how did Holmesburg come to be here? Why in the late 1600’s did a village begin to grow at this particular spot along Pennypack Creek? Is there some special feature of the creek at this spot which made the early settlers say "This is the place!"? Yes indeed there is. What made this an important location for development along the creek is a geological feature known as the fall-line.

The Pennypack’s fall-line is the point where the creek flows over the last sets of rapids and drops almost to the level of the Delaware River. From the fall-line on out to the Delaware, the Pennypack is a tidal creek and changes from shallow to deep and back again in a cycle repeated twice daily as the tide rises and falls on the Delaware.

You can see the fall-line for yourself as you walk across the old bridge on its downstream side. The fall-line is the set of rapids immediately downstream from the bridge. It is not a dramatic feature of the landscape but it has shaped our local history by the way it effects the flow of the creek Upstream from the fall-line the creek is normally shallow enough to wade safely. Downstream from the fall-line the creek is too deep to wade at high tide but provides water deep enough to float boats. In fact on a good high tide the Pennypack could be used as part of a water-highway from the heart of Holmesburg all the way to the Atlantic Ocean!

From the earliest days, people in this area noticed the fall-line and took advantage of it. Sometime deep in prehistory Indians established a trail through here which crossed the creek at the fall-line. When Europeans arrived they continued to use this trail, making it their "King’s Highway", and William Penn had his bridge built here in 1697.

In addition to being the best crossing-point, the fall line provided early colonial industrialists with two things they needed: water-power and transportation. A natural water-fall upstream from the bridge became the foundation for a mill-dam. (The old "Holmesburg Dam", now "Rocky Falls".) The mills themselves were built not at the dam but about a quarter of a mile downstream, below the fall-line, on a stretch of the creek where the high tide provided water deep enough to float small cargo boats. Water to turn the mill-wheels came from the dam to the mills through a long mill-race.

The mill owners took full advantage of their location: water-power ran a saw-mill turning logs into lumber and a grist-mill grinding grain into flour and meal. High tidewater on the creek allowed raw materials and finished products to come and go by boat, an unusual advantage which made the old "Pennypack" mills especially important in early Pennsylvania history. Farmers came by boat from New Jersey, rowing up the creek to bring their grain to be ground at the mill which had a kind of dock or wharf right on the creek. Barrels of flour and meal were shipped down the creek to the Port of Philadelphia and beyond; to the West Indies and Europe. So important was this mill that Welsh farmers who had settled in Montgomery county built a road to bring their grain to the mill. (We still know it today a Welsh Road. Follow Welsh Road to its end and you will find Mill Street which leads directly to where the old mills once stood.)

Being situated at the fall-line area, the Pennypack mills prospered and the mills helped make early Holmesburg. With the mills came the need for workers and housing for them. Merchants set up shops to supply their needs. The local population increased and flourished. Schools were established. Congregations formed and built their churches. The intersection of the Welsh Road and the King’s Highway became a convenient place for travelers to pause for rest and refreshment. Several hotels were established and continued in business all through the 1800’s.

In 1803 the Frankford and Bristol Turnpike Company was formed and Holmesburg got its own toll-house and toll-gate. In 1868 the Bustleton railroad was built through Holmesburg, carrying both passengers and freight. The freight included coal to fuel the new steam-engines which now replaced water-power to run the mills.

With steam-power running the mills and the railroad transporting goods, the Pennypack began to lose its importance in the local economy. By 1905 lands along the Pennypack had been acquired for parkland. The mills, now in disrepair, were torn down, clearing the way for recreation.

But the creek still flows through the heart of Holmesburg, under the old bridge and across the fall-line where the tides still rise and fall in the ancient rhythm. Walk across the bridge and take a look for yourself— see the reason why a town grew here, at this particular spot along the Pennypack.

America’s earliest history reflects the shape of the land and the way its waters flow or shift with the tide. The nature of the land determined what happened here. At Pennypack Creek’s fall-line in the heart of Holmesburg, nature and history flow together.

A fall line is an unconformity. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls. Many times a fall line will recede upstream as the river cuts out the uphill dense material, many times forming “c” shaped waterfalls. Because of these features river boats typically cannot travel any farther inland without portaging unless locks are built. On the other hand, the rapid change in elevation of the water, and the resulting energy release, makes the fall line a good location for a water mill. Because of the need for a port and a ready supply of water power, settlements often develop where rivers cross a fall line.

In the 19th Century, the fall line often represented the head of navigation on rivers at points like Little Falls or the Great Falls, on the Potomac River. However, since the advent of flumes for water supply and canals for shipping in the early 20th Century, the most prominent feature of fall line settlement was the establishment of the cities along it. As the cities were linked by the early highways, U.S. Route 1 and Interstate 95 came to pass through many of these cities, roughly tracing the fall line.

To claim this EarthCache: 1) go to the coordinates and take a photo of yourself and GPSr at the Fall Line here. 2) Email the two prominent colors of rock at the Fall Line. One is prominent and the other is almost squeezed (i.e. The Geomorphic Process of a fault line) between the other. 3) Take a photo of either the "Rocky Fall" or the "Holmesburg Dam" or a view of the river towards where the Mill would have stood.
Post the photos in your log and send the email and you are good to go!!!

If your picture is not ready then wait until you have a photo. Logs with no photo of the actual cacher logging the find or failure to answer questions will result in a log deletion. Email me if you had any difficulties or problems, as I understand that things can happen we don't expect. Thanks.

I love it when a cache comes together, Strike Anywhere!

MORE INFO: Just recently, members of the natural lands reclamation division of the Fairmount Park Commission effected the removal of the Holmesburg Dam (1699): a structure of unquestionable historical significance that powered a combination sawmill and gristmill for much of the 18th century. The dam was the last vestige of a complex that one stood on the distant fringes of an international colonial trade network. At high tide, grain and lumber from the mill complex south of Frankford Avenue was shipped via shallow draft boats to Philadelphia and distant colonial ports. Weakened by floods, the dam was breeched by Park ecologists to allow fish passage. Most other dams in Fairmount Park waterways dating from the 1920s-1930s were designed to create recreational swimming holes. Though structurally sound, these dams lack the historical weight of Holmesburg and are similarly threatened.
Thanks to Roland Williams for most of the above History. S'nice!

Additional Hints (Decrypt)

Gurer vf n fvta gung gryyf nobhg gur qnz arne TM ohg vg unf orra qrsnprq n yvggyr gbb zhpu. Uvtu gvqr be ybgf bs enva jvyy uvqr fbzr bs gur angheny ornhgl bs guvf trbybtvpny svaq!

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)