The Ringing Rocks of Pennsylvania:
A Musical Mystery along the Delaware

N. A. Reiter

17 August, 2006

Chimes across the Hills:

Not far from the broad and ancient waters of the Delaware River, and a little bit west of the village of Upper Black Eddy, Pennsylvania is a field of enigma where strange musical notes arise from the very bones of the earth, to waft across the hills. From the lore passed down to the early white settlers of the area by Native people, it is clear that even a thousand years ago, sojourning Indians puzzled over the strange properties of the place that came to be called Ringing Rocks.

I first heard of the Ringing Rocks mystery several years ago, and considered it to be one of those places that would have to be on any good Fortean travel itinerary that took in points east. It slipped from my radar for quite some time, though, as family vacation trips and lesser weekend travels never quite took me in that direction. When some family debate ensued by about May of this year as to where, if anywhere, we would be taking off toward for a road trip, a "Mysteries of Pennsylvania" travel package was tabled. With gasoline over $3.00 a gallon, the prospect of some of the more traditional longer trekking induced a precognitive ache in my wallet. Plus, assorted issues within the family made it likely this year's summer adventure would be truncated anyway, time-wise. With only my youngest son Ian left in high school and even him being wrapped up in his rock band, the era of the family road trip seemed like it was coming to its end. Well, maybe we could make one more in our old style. There was certainly enough of a more conventional vacationing potential available in a Pennsylvania road tour apart from the odd-side.

All was agreed upon, and in my off time I dove into finding mysteries to fill the miles. The Ringing Rocks came back to front and center of my attention, and I eagerly did as much web-searching on the topic as I could...

The accounts varied somewhat, but a coherent picture soon emerged. Near Upper Black Eddy, in a heavily wooded area of gently rolling hills, was a startlingly open field of large bare boulders. The boulder field comprised about five acres. From the times of the first white settlers of the area in the mid 1700s, strange stories of the barren expanse of tumbled rock were passed through the generations, adding to the rumors passed on by the Indians. Apart from the obvious dramatic appearance of the boulder field, two other key aspects of lore were associated with it. First of all, the boulder field was extremely devoid of life. Birds would supposedly not fly over it; animals would not suffer to come near. No plant life could be found away from the fringes of the surrounding forest. By outward appearance, it was infernally cursed. Secondly, and more to the core of the legend, it was said that many of the rocks in the field would ring like metallic bells when struck. Some tinkled like dainty chimes, others sounded like deep gongs. Not all boulders in the field had this property, but strangely, there was no visible way to tell the "ringers" from the "non-ringers." However, it was agreed upon also that while some of the rocks in the field would ring, none of the rocks in the surrounding forest - of which there were multitudes - would give any tones at all, other than the usual "thump." The property of ringing was somehow tied to the mysterious field of rock itself.

The legendary property of "no life" in mystery spots is not unique - there are quite a few other dead zones to be found around the world. The Devil's Tramping Ground, in North Carolina is one of these, at least in folklore and tradition. (When I visited the "DTG" in 2002, I found quite a bit of plant life, as well as beer cans, wrappers, used condoms, etc) Rocks that ring like bells are a bit harder to come by, though.

A number of local scholars and sleuths over the decades have visited Ringing Rocks - now a Bucks County, PA park - and have tried to solve the mystery of the ringing. Some claim the ringers are hollow. Other theories say the ringers have some form of built in stress - like tempered glass - and are harder than non-ringing boulders nearby. Still others suggest that some earth energy anomaly of the field area produces the ringing effect... and also has been said to make compasses spin and electronic devices go crazy. Even Native Indian curses are mentioned from time to time.

Several names who remain immortal in the chronicles of anomaly research and unsolved mysteries devoted time and attention to Ringing Rocks. Most notable among these perhaps was the writer and zoologist, Ivan T. Sanderson. Sanderson concluded in his 1967 classic "Things" that at Ringing Rocks Park, "something was not right here..." Sanderson investigated the acoustics of the ringing rocks, as well as the idiosyncrasies of the nearby plant and animal life.

In addition to those people working in the realm of science, musicians and artists have also not overlooked the Ringing Rocks. Local musicians and recording professionals have played whole compositions on selected rocks, much like Ben Franklin on his glass "armonica". For all who visit, it seems that the chiming boulders do not fail to invoke a child-like awe and magical spell.

Our Visit:

In the weeks before our trip, I watched the national news and weather forecasts nervously. The Mid-Atlantic States were under the torment of nigh endless rain, and the worst flooding since the 1950s. The Susquehanna and Delaware rivers flowed up out of their beds to engulf highways, homes and properties. Finally, about a week before we were slated to depart, the rain stopped, and the rivers began to recede. While I felt deep sorrow for those who lost property, pets, or even loved ones in the flooding, I also was inwardly and unabashedly thankful that the roads would likely be open for us on our travel route.

The state and local highways near the Delaware River, from Delaware Water Gap down past Easton were not unscathed, and some sections remained closed. Stoic inhabitants continued to squeegee mud from their basements, or were slowly re-opening their businesses. Nevertheless, the road was at least open to Ringing Rocks Park, and it was near noon, on the 4th of July, when we arrived.

Several other cars and trucks populated the tree shaded parking lot. From the gravel lot, a path of about 500 feet winds through the boulder piled woods to suddenly burst out into a sunlit scene that would indeed remind one of the Led Zeppelin album cover for Houses of the Holy. Or perhaps a set that Chuck Heston would have scrambled over in Planet of the Apes... (click pic to enlarge)

My son Pete volunteered to play the pack mule for me, and helped lug the instruments to the edge of the rocks. For all the other vehicles in the lot, I was surprised that only one young couple on the far side of the boulder field could be seen. The others must have been off picnicking or hiking. A thrill ran through me. What a strange looking vista!

I set up a "base camp" perhaps 100 feet into the boulder field, and made rock-hopping forays from there. My spouse and Pete had already resigned themselves to a long wait, and found spots on some shady boulders near the eave of the woods to stretch out and count the minutes until I was satiated.

I brought the following "Ye Olde Avalon" instrumentation with me:

• My LOHET Hall gauss-meter for sniffing the local magnetic ambient.
• A magnetic compass
• My GPS
• The digital and film cameras.
• My Geiger counter
• An ultrasonic converter and detector for examining the possibility of ultra-high pitched rock noise.
• A heavy duty claw hammer for whacking on rocks.
• A miniature cassette recorder

For the next hour or so, I scurried about the boulder field like a sweaty Dahl sheep hammer-whacking on this rock or that. Several groups of visitors climbed out into the field while I was making notes and taking readings, and I cheerily explained myself while keeping a little cryptic mystique going for fun.

The rocks were an addiction. They rang! Really truly rang! To me it seemed like about every 5th or 6th large stone was a ringer - the others sounded like respectable stones are supposed to sound - thwack thwack or at most tik tik. When you hit a ringer, you know it. Here is a little MP3 of a nice low toned one:

My oldest son Trevor was able to capture a couple of the recorded ringing blows with a Fourier transform spectrum analyzer download. The frequency spectrum of the ringer you hear is shown thus:

Notice that while the fundamental appears to be at around 1.7 KHz and a second harmonic is seen at about 3.5 KhZ, there are a couple of other frequencies present as well. The ringing is complex.

One also cannot predict the sound you'll encounter. Some large door sized boulders gave a dainty chime, smaller ones - maybe bushel basket size - gave deep gong like tones. This is a key clue - save it for later.

In succession, I used my various instruments in the field, walking about with them and comparing readings to later ones taken out of the field in the woods and along the trail to the parking lot.

As time went by, from across the rocky waste, I could feel impatience and heat stress rising from the family. I slowly pulled the operation in, collected the family, and headed back to the woods. As we followed the main trail back to the parking lot, I tried striking as many available rocks as I could reach. No ringers. Only thud.

Before leaving we had a late lunch picnic out of the cooler. As I ate my turkey sandwich and blueberries, I realized I was beginning to develop a killer headache. This stayed with me for the balance of the day, as we zigzagged slowly toward Philadelphia and our motel. Strange emanation from the ringing rocks? Or a daft out-of-shape white guy without sunscreen on a hot day pretending to be a mountain goat too long?

What the Rocks Told Me:

The popular lore of Ringing Rocks likes to point out that nothing grows in the boulder field, and no animal life is to be found there. This did not appear to be quite true, as several small struggling saplings have come up through the rocks, out into the field a ways. Truthfully, the appearance of "no life" may well relate to something not immediately obvious - the depth of the boulder pack! Some measurements have found that in places, the pile of rocks making up the field is over fourteen feet deep. The ringing rocks are not a scattering of boulders on the ground, extending out from under the surrounding woods - rather, they are a deep extended pile. Somewhere far below the walk-able surface is solid ground. In many places where I could peep between rocks, I could see nothing but deeper rocks to the limit of my vision. My presumption is that the victorious saplings must have gotten their start on a shallow hump of soil rising like a shoal from under a sea of stone.

Ivan Sanderson claimed not to have seen any animal life in the rocks. Others say that spiders and snakes probably lurk. I found a couple of little fast black spiders, and a dainty iridescent dragonfly came to visit as I was whacking on an oddly shaped ringer. I have to suspect that mammalian life does not frequent the rocks simply because there is no need to. No food, why bother? On the other hand, I will state for the record that while I was in the boulder field, I saw no birds flying overhead, and truthfully saw or heard none in the woods near the field. That struck me as peculiar. Nor did I see any sign of bird droppings on the rocks. Come to think of it, the amount of lichen on the rocks appeared to be pretty sparse as well, though it was present. The Ringing Rocks are comparatively very clean. (click pic to enlarge)

What about the rocks themselves? The uniformity or homogeneity of the boulder field is striking. All of the rocks are of the same color and texture - medium grey-tan with occasional brownish patches of iron oxides. Long ago, the composition of the stone in that area was identified as diabase - a mafic igneous rock similar to granite or basalt, but with an internal grain or crystal size smaller than the former but larger than the latter. Diabase is a common stone along the Delaware River valley. It is very hard, dense, and ancient, usually forming at volcanic ridges and dykes. Diabase contains a blend of minerals: quartz, alumina, phosphates, feldspars, oxides of iron, and olivine among others. Where broken ends or split rocks were found, I examined the internal colors and textures. The insides of the ringing rocks sparkle dully with little crystals perhaps a millimeter or so across, of a color blending dark chocolate brown, black and deep greenish. The igneous composition and high natural density of diabase offers further clues to the ringing - let's add this to the evidence.

I looked for relations between form and tone - keeping in mind the well known laws of mechanical resonance. After all, ringing in a bell, chime, tube, or even rock, is a function of mechanical resonance where size, shape, density, and composition all play roles. For the Ringing Rocks, the composition seemed to be well established! What else could affect ringing?

One needs to look for basic properties. First of all, as mentioned previously, the size and shape of the ringers did not seem to correlate with tone. A couple of very large rocks had dainty high tones. A smaller fellow was low and throaty like a brass bell. Therefore it might be inferred that the ringing has to do with an internal property of the rocks such as density or hardness. Size doesn't matter at Ringing Rocks Park...

But yet it does in a way. Along with the non-conformity to size and tone, I did discern another clue. All of the ringers were actually larger rocks. The smallest ringer I could find out of perhaps 20 or so good ones was about the size of a basketball. Nothing smaller than that - including shards found to be broken off - produced either an audible ringing or even an ultrasonic one.

Two other stars of this "rock concert" disclosed some valuable truth to me...

In one case, I discovered a slightly oval boulder maybe 30 inches by 20 inches that had two distinct ring tones, depending on where I struck the surface with my hammer. Here is another little audio file:

As we saw previously, these tones can be shown graphically by their frequency spectra:

Even more interestingly, I found a large slightly flat pear shaped boulder that at some time in the long ago past had developed a diagonal crack through part of the "wide" end. This crack had opened slightly, and was weathered, however the portions of the parent boulder were still pressed or stuck together. The larger portion of the boulder rang with a tenor "ting". However the somewhat smaller portion on the other side of the crack did not! It was as dull sounding as a piece of wet clay. (click pic to enlarge)

Some people have speculated that the ringers are hollow. I could not find any evidence for this, at least not as far as I could tell from broken sections or rocks with cleaved faces. If some of the rocks in the boulder field were hollow, one would find the "shells".

What about claims of compasses going awry and electronic devices not working?

With deference to the truth that geophysical anomalies don't always occur at all times, I would have to offer that the jury has to remain out with regards to such claims of anomalous energy phenomena:

1. I did not see any noticeable deviation or unusual motions of my magnetic compass.
2. The Hall gauss-meter did not detect any noticeable deviations in the earth's magnetic field for the regions I examined. I also did not detect any magnetic fields or magnetization around any particular boulder checked - ringer or non-ringer. The diabase certainly contains oxides of iron, but not enough magnetic Fe3O4 to affect the meter, which is sensitive to about one decade beyond the earth's field.
3. I did not notice any difficulty for my GPS in quickly acquiring satellites for positioning. My position was: 40d 33' 44.64" N 75d 07' 46.02" W
4. There did not seem to be any noticeable difference in background radiation using our Geiger counter, from the boulder field to the woods. CPM ranged from about 40 to 80.
5. I did not hear any unusual down-shifted acoustic energy using the ultrasonic sniffer.

One question that had been asked of me by my chum Andrew before leaving on our trip was whether or not the ringing rocks would ring if they were taken from their boulder field. I found that this had also been addressed apparently by local researchers early on in the 20th century. If a ringer is taken from the park, it indeed continues to ring. The sign at the driveway entrance states that it is illegal to remove rocks from Ringing Rocks Park. And considering that the smallest ringer I could find with my hammer was heavier than anything I could tote any appreciable distance without a winch or sling, the point was overall pretty moot.

It's not to say a few small chips of stone from the pile didn't get stuck in my shoe, and on one occasion I hit a ringer rather hard and golly, another chip flew into my pocket. A lot like those times crop circle soil from Canada crossed the border on my boots. Darn muddy boots. Darn stone chips.

Sometimes it pays to not just consider what a thing is like, but how it fits in to its environment as well. As I scanned across the ruinous boulder field, I found it difficult to map out mentally the overall shape of the rocky region. Recently, I took a gander at the area courtesy of Google Earth. The ringing rocks boulder field is roughly teardrop shaped, with a narrow band of rocks to the north, connected to the main field by a run or path of more rocks. See below: (click pic to enlarge)

I have seen boulder fields before. But they have always been at the base of a cliff or mountain. Devil's Tower in Wyoming comes to mind. Here though, there is no mountain or cliff or glacial scouring for rocks to split and fall from into a pile. There really doesn't seem to be much of a reason for it to be there, in the midst of the forest. But there are many things that just seem to not need a reason...

The Carillon of Enigma:

From lore, anecdote, and the clues given to me by the bone of the earth on that July 4th afternoon, I'm not able to conclude that there isn't a mysterious component to the Ringing Rocks story. Ivan Sanderson was right, I believe - there is something strange going on there. But I also believe the answer to the ringing part of the mystery lies within the rocks themselves.

As I hopped from boulder to boulder swinging my hammer like a crazed mountain dwarf, I was not overwhelmed with any mystical sensations or subjective impressions of intense "power." I developed an ass kicking headache, true that. However, I would have to confess that there was another sensation that lingered with me for a time after we drove off - a feeling of connection to the earth element. I think the rocks were talking to me all the while, ringers or otherwise.

So why do the ringing rocks ring? Let's consider the clues in review:

1. About 1 in 6 rocks ring.
2. All the rocks in the boulder field appear to be diabase of similar outward appearance.
3. They do not appear to be hollow or have voids.
4. They are randomly stacked in a vast pile, in places up to 14 feet deep.
5. Being in the open air, the rocks probably are heated and cooled more strongly with day and night than their woodland cousins are. They are also cleaner.
6. The boulder field rocks are not resting on moist earth - they are supported at points by contact with their neighboring rocks! Any sort of mechanical resonant structure will ring better when supported at a point or points only. A hand bell does not ring when a soft hand is cupped around it and absorbs the acoustic energy.
7. The ringers tend to be the larger boulders.
8. Some ringers can have multiple tones, indicating a non-homogeneity or un-evenness of internal density or structure.
9. A large chunk cracked from a larger ringer did not ring.
10. Size of the boulder does not necessarily correlate to tone of ringing.
11. I did not observe any unusual EM or measurable energy phenomena there at the park.
12. The rocks - ringers or otherwise - are not noticeably magnetic.
13. The internal appearance of broken faces or stone chips does not show any visible difference in color, grain size, or texture between ringers and non-ringers.

One other clue of a very unique sort that came our way needs to be mentioned here...even if that clue showed up literally three days before we made it to Ringing Rocks Park!

On July 1st, as we were driving from Greensburg to Williamsport, we passed near State College, PA and saw signs for several caverns in the region. Every vacation trip needs to have a little caving - even if family style. I opted to drag the family to Indian Caverns, about 12 miles west of State College. Indian Caverns was a fabulous throwback to the 1950s golden era of roadside attractions across America. It is indeed an interesting cave as cave systems go, although only the upper levels are open for the public to tour. There were several very unique "stops" within Indian Caverns. One of which is a rock wall with small deposits of radium that glow like fireflies when the tour guide turns the lights out. Another room in the cave had been a burial tomb for an important official of the Susquahannock Indian tribe in some long ago era.

And...there was also... a ringing rock!

About 2/3 of the way through the tour, visitors are lead past an oddly shaped thin "fin" of rock that sticks out from the cave wall. A wooden mallet is provided to take a whack. The rock rings with the same tones as I heard three days later at Ringing Rocks Park. Bucks County PA does not have the only singing geology in the state it seems! Check them out online: www.indiancaverns.com

It is very important to note that while the "ringing rock" in Indian Caverns gave a fine strong ringing tone like any number of the park ringers, it was of a much different composition! The park rocks are diabase - volcanic igneous rock. In Indian Caverns, the rock is nearly entirely limestone and calcite travertine - water deposited "flowstone" or calcite. (click pic to enlarge)

Sometimes we have to apply the wonders we know to explain the wonders we don't. From all the clues I was finding, I began to conclude that the ringing of the rocks at Ringing Rocks Park was probably not in and of itself paranormal, but rather is uniquely acoustic.

The act of ringing is the act of resonant vibration. Any solid object with some density and structural hardness will ring, if it is of a proper size and is suspended correctly. Metals are not the only material to ring. Bells and chimes can also be made from glass, carved crystals, and ceramics. Diabase is very hard, comparatively dense, and conducts sound well, due to its poly-crystalline nature.

A true bell is a fantastically complex device acoustically. Man made bells - such as classical church bells - produce their clear ringing sound by addition of many preferential wavelengths of sound produced all at once in different parts of the bell. The classic shape of a bell contributes to its special ringing ability. Chimes are simpler devices, relying more on a fundamental resonant frequency of a tube or bar. The Ringing Rocks would probably be better described as chimes than bells.

The wide range of tones versus rock size implies that the material of the rock and its internal disposition is the primary factor determining ring tone. For bells, chimes, or any ringing structure, an overwhelmingly important factor is the speed of sound within the material making up the structure. The formula for this is given as V = (E/D)½ in which V represents the velocity of longitudinal waves (in effect, the speed of sound through the material), E is Young's Modulus, or elastic tension in a solid, and D is the density value (mass per unit of volume). Using this formula, the speed of sound in a given solid V is obtained as a figure equal to the square root of the quantity produced by dividing Young's Modulus E by the density of the mass D. Therefore, the longitudinal vibrations in bell metal are proportional to the square root of the metal's elastic tension (in this case internal stress) and inversely proportional to the square root of the density.

By virtue of its nature, igneous rock often has considerable internal stress - especially fine grained rock and volcanic glasses. These stresses might easily modify the tone or pitch of the rock's resonant ring. A cylinder of tempered glass - containing a high degree (many thousands of p.s.i.) of internal stress will ring with a higher sound than softer annealed glass, if identical chimes are made from each. It is distinctly possible that many of the rocks at Ringing Rocks Park are ringing away at frequencies below human hearing. The ones we hear so delightedly are the ones possibly having a much higher internal compression or tension. It is also possible that many of the rocks in the nearby woods would ring as well... if they weren't resting on soft earth, but were instead propped up at single points against other rocks.

Both the two toned rock and the cracked rock with the silent smaller section suggest as well that internal stresses (or relief thereof) in the diabase matrix play a key role in ringing and tone.

Echoes:

In the end, it may well be that the Ringing Rocks simply ring because they are very hard and dense, with internal stress, and they are in a unique position of being propped up in a large pile where they are free to ring when struck, like bars on a glockenspiel. They don't appear to be hollow, nor do they appear to possess strange forms or amounts of latent energy.

I hope the reader has not been disheartened by my words on this matter, though. For me, at least, unique but otherwise realistic acoustics do not diminish the Rocks' distinctive beauty and magical pneuma. There is, after all, the greater mystery of why the Ringing Rocks are there in the first place - piled up in the midst of Penn's Sylvan Arcadia like they were gathered there by a giant's construction crew in remotest antiquity. And why the birds and bees really don't appear to fly near the place...

As I took in one last look across the Ringing Rocks that July afternoon, before turning to go into the woods, I recall my inner voice saying to me, "the rocks were brought here..." The everyday rational mind replies, "Why? By whom? How? If Native people dragged them here, why did they not make a temple or effigy space? Do the rocks cover something that was not intended to be found?" But by that time, the inner voice has fled.

You can listen to a woman singing, and understand the acoustics of her voice even as you appreciate it for its beauty. But if her words are sung in an ancient tongue, the mystery remains... The voice of the Ringing Rocks may arise from the earthly wonder of crystals and stresses of a volcanic birth, yet the words lifted in song across the Delaware River country will probably never yield up an easy explanation. Best to go there yourself, and let them sing to you!

References:

1. Sanderson, Ivan T. "Things." New York: Pyramid Books, 1967
2. Corliss, William R, "Unknown Earth: A Handbook of Geological Enigmas" Glen Arm, MD: The Sourcebook Project, 1975.

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