Ringing Rocks Park

W. W. H. Davis's History of Bucks County, published in 1876, placed the "Ringing rocks" on the farm of a Mr. Lippincott, near the Delaware River in what was then Nockamixon Township. Davis gave the field about four and a half acres of boulders, from a few pounds to several tons, piled "to an unknown depth" with no earth, tree, or grass between them. When struck, he wrote, they "give out a peculiar metallic sound, the tone of each differing from the other." A moderate-sized dog, he added, could creep down among them 10 or 15 feet.

The 1890 concert

In June 1890, at a meeting of the Buckwampun Historical Society, Dr. J. J. Ott of Pleasant Valley played several tunes on a set of stones chosen to form an octave, striking them with a steel hammer while a brass band accompanied him. One of the tunes was "Home Sweet Home." B. F. Fackenthal Jr. wrote in 1919 that "the clear, bell-like tones of the rocks could be heard above the notes of the horns."

Ott's stones came from Stony Garden, a separate boulder field on the northern slope of Haycock Mountain, where that meeting was held. Lewis Sigafoos, writing up the society's history in 1935, said that so far as he knew the performance had not been repeated.

Ownership

The Buckwampun society held a later meeting at this field. One of the papers read there came from Abel B. Haring, president of the Union National Bank of Frenchtown, New Jersey, who owned the land. On August 22, 1918, Haring gave it to the Bucks County Historical Society: 7 acres and 8.08 perches, with a right-of-way from the public road that John O. McEntee agreed to give.

The historical society visited on October 4, 1919. Fackenthal read his paper afterward under the hemlocks at High Falls and struck a flat stone he had carried away from the field the week before, to show that a rock keeps its ring once moved. The land later passed to Bucks County, and the park now covers 128 acres.

How the field formed

The Pennsylvania Geological Survey describes the site as one of the largest diabase boulder fields in the eastern United States. The diabase arrived as magma about 200 million years ago, at the start of the Jurassic. During the Ice Age, repeated freezing and thawing broke large pieces off the fractured bedrock, and in cold summers the boulders slid slowly downhill on slippery permafrost.

Why some ring

Not every boulder rings. Fackenthal heard some with "tones like those of a blacksmith's anvil" and some that "do not ring at all," and wrote that why one rings while the rock beside it is silent "does not to my mind fully appear." In 1909, New Jersey state geologist Henry B. Kümmel collected a ringing sample and a silent one here for J. Volney Lewis, a geology professor at Rutgers, who examined thin sections of both. Both were olivine diabase. The only difference Lewis found was that the pyroxene in the silent rock had altered, while every mineral in the ringing one was "remarkably sound and fresh."

In December 1970, John F. Gibbons II and Steven Schlossman published "Rock Music" in Natural History, on the Bucks County rocks. Later accounts of the paper say that cores sawed from ringing boulders changed size within days of cutting and cores from silent ones did not, which pointed to stress held inside the stone. Those accounts disagree on whether the ringing cores shrank or swelled.

The survey's 2016 sheet on the site puts the cause down to "a delicate, complex balance of conditions, including mineralogy, weathering properties, and microclimate." In its account, pyroxene near the surface weathers into clay and expands, putting the boulder under tension, and boulders that stick up into the sun away from the shade of the woods are among those that ring. Lewis's 1909 samples had pointed the other way, with the altered pyroxene in the silent rock. In February 2026, Commonwealth University geologist Brett McLaurin told WITF that a church bell rings because it is free to move, while a boulder wedged tightly between others cannot vibrate. He called the cause "a combination of factors coming together."

Estimates of the share that ring vary. The survey reports visitors' figures of one in six and one in three. In 2020, engineers from the acoustics consultancy Acentech struck 534 rocks and counted 167 that met their test for ringing, about 31 percent.

The compass

The survey notes that "numerous legends have been advanced" about the boulders. One holds that a compass stops working over them. Helen Delano, a scientist with the survey, told WHYY in 2013 that she had tried it. "A compass still works."

The park is open daily from dawn to dusk, and there is no entrance fee. A hammer is the one thing to bring. A standard hammer works as well as a geologist's rock hammer, and it may take a few tries on different boulders before one rings. A visitor told WHYY in 2013 that the boulders that rang for him were the ones already carrying hammer marks.

The boulder field is a few minutes' walk on a flat trail from a small parking area that can fill on weekends, and arriving early helps with both parking and summer heat. Portable toilets and a picnic area sit near the lot. The boulders are uneven and can be slippery with rain, ice, or dew, and the county recommends sneakers or rubber-soled shoes for crossing them.

High Falls, the largest waterfall in Bucks County, is about 5 minutes on foot from the boulder field. Its flow follows the rain. It runs strongest in a wet spring, a dry summer can reduce it to a trickle, and in a hard winter the whole cascade can freeze. The county does not maintain the trails in winter, when they can be icy or snow-covered.