Pennsylvania Historic Preservation

Blog of the Pennsylvania State Historic Preservation Office

Large pile of small stones around a large boulder in woods
Large pile of small stones around a large boulder in woods

Finding Meaning in Stone


Nothing excites the imagination like an unanswered question, and since spring I’ve been exploring a little-recognized mystery here in Pennsylvania. 

New England has a tradition of dry-laid stone cairns, walls, and chambers that have been variously interpreted over the years as colonial field clearing piles, industrial remains, Celtic structures, Native American memory piles, astronomical observation sites, and sacred places. 

We are slowly learning that these structures also exist in parts of Pennsylvania, and this was recently highlighted by a site in Berks County that made me pause and say, “What’s going on here?”

The Oley Hills Site, Berks County

In early March, I spent my last, best pre-COVID site visit in the hills of Berks County at a stone landscape complex known as Oley Hills. 

The complex contains numerous constructed stone features such as platforms, cairns (cairn is defined by James and Mary Gage as “an intentionally constructed pile of stones”), curved stone rows, and row-linked boulders built on the top and eastward slope of a broad ridge.  Central to this complex is a large boulder that sits perched at the edge of the ridge. 

Large boulder in forest
The large boulder or tor that is a central component of the Oley Hills site.

While the traditional archaeological perspective would attribute these constructions to historic-period field clearing practices, these features exhibit a level of careful, labor-intensive, and at times artistic effort that does not readily conform to the idea that they are agricultural in origin.

The site was identified by Fred Werkheiser, a shoe salesman and local historian/avocational archaeologist from Bethlehem.  In the late 1990s, Werkheiser shared the site with Norman Muller, an art conservator from Princeton and member of the New England Antiquities Research Association (NEARA) who has investigated and published on numerous stone landscape sites throughout New England. 

After consulting with PHMC archaeologists, Muller investigated the Oley Hills site through archival research, geologic assessment, and mapping the site with the assistance of John Waltz, a surveyor and engineer.   Their investigations included attempts to date the site’s construction through various analytical methods. 

Large pile of small stones in woods
A flat-topped cairn at the Oley Hills site that is connected to a low curved stone row.

Although the tests conducted so far represent very small samples, they have all yielded results that pre-date European contact.  Drawing on site comparisons, historic-period observations of Native American practices, and landscape archaeology theories, the team has interpreted Oley Hills as a possible Native American ceremonial site.

The So-Called “Stone Mound Problem”

The idea that there could be a pre-contact ceremonial stone site – let alone any stone constructions of Native American origin – in eastern Pennsylvania is generally inconsistent with what we have learned from archaeological excavations. 

The lack of traditional archaeological evidence (coupled, no doubt, with a reaction against exotic theories claiming that these sites were built by Celts, Vikings, or Phoenicians) has led archaeologists to explain these features in terms of historic-period agricultural practices.  There is no doubt that some of these features represent boundary markers, field clearance rows, and the more obvious walls, foundations, and enclosures. 

But the issue is not so straightforward, as research groups and stone feature enthusiasts have long questioned the level of effort and care represented by some of these constructions, and instead argue that they represent Native American burials, effigies, ceremonial sites, and astronomical calendars.

An Important Dialogue

In a 2007 resolution, the United South and Eastern Tribes, Inc. (USET) declared that “within the ancestral territories of the USET Tribes there exists sacred ceremonial stone landscapes [CSL] and their stone structures which are of particular cultural value.” The resolution went on to state archaeologists’ interpretation of stone features and landscapes as the result of farming practices has not only left these sacred sites vulnerable to development, but passes judgement on their significance and protection, or lack thereof. 

This resolution was shortly followed by the first National Register determination of eligibility for a CSL in Massachusetts in 2008.  USET has since collaborated with other agencies and organizations on CSL inventories, survey standards, and training opportunities.  Interestingly, a 2016 USET resolution on this topic specifically identified “concentrations of pristine ceremonial stone groupings” in Pennsylvania.

Pile of rocks in woods
Photo from the PASS file for 36SQ0195, a field of approximately 120 cairns in Susquehanna County. Consultation with the Oneida revealed that the site could be related to a sacred stone landscape.

Recent literature relating to stone features recognizes the inherent duality in which both explanations are valid.  More importantly, there is an increasing recognition that discourse about memory, patrimony, and cultural identity and marginalization is central to the study of CSLs. 

Researchers are sharing respectful methods for documenting and investigating features, ways to distinguish Euro-American historic stone features from those that are Native American in origin, and guidance on evaluation. 

The underlying recommendation is that these studies be conducted in consultation with Native American tribes

Constructed Stone Features in Pennsylvania

While this phenomenon is common in New England, the occurrence of these stone features and landscapes in Pennsylvania is less well known. 

Due to the history of conflicting interpretations, when these sites were recorded, they were inconsistently classified as burial mounds, earthworks, and “Other Specialized Aboriginal Sites” – to name a few.  Until recently, we did not even have a feature type that could represent these stone stacks of unknown function. 

There are 35 recorded sites across Pennsylvania that contain ambiguous stone constructions.  The majority of these are cairn clusters ranging in size from a single cairn to fields containing 120 features. Specific information from CRM surveys and NEARA members suggests the potential to record at least 25 additional sites in northeast Pennsylvania alone. 

County map of Pennsylvania
Green counties contain recorded stone cairns or features, whereas blue counties are reported to contain cairn fields but none have been recorded as of yet.

While there are a handful of cairn sites recorded across western PA, we have more recorded sites in eastern PA, as well as feature-level GPS data provided by AECOM from a recent pipeline survey.  Regardless, due to the patchy nature of our eastern PA sample, we can only present a few cautious observations. 

In our current dataset there appears to be two primary clusters. In the northeast, there is a band of cairns and cairn fields built from the local sandstone of the Devonian Catskill formation.  The largest cairn fields known in Pennsylvania are concentrated in this area, and the Pennsylvania CSL identified by USET is located in this region. 

In the southeast there is a small cluster of sites that, like Oley Hills, exhibit a greater variety and complexity of feature types, including cairns, platforms, stone circles, possible effigies, and boulders that are connected by stone rows.  In addition, some of the features within these complexes appear to exhibit astronomical alignments, and others were constructed in association with visually-striking natural landmarks such as large boulders. 

Large pile of small stones around a large boulder in woods
Another flat-topped cairn at Oley Hills that is built onto a bedrock outcrop and integrating a large boulder.

These sites are situated along the Oley and Perkiomen-Lehigh Paths, as identified by Paul Wallace.

Filling in the Gaps

Because the Pennsylvania dataset is so fragmentary at the present time, it is difficult to analyze distribution trends and site characteristics. 

After the successful site visit to Oley Hills, we have begun to work with NEARA’s Pennsylvania chapter to encourage recordation of these sites and landscapes.  We would welcome more input as we begin to fill these gaps. 

Please contact Hannah Harvey ( if you are interested in recording sites or sharing stone feature data from previous surveys. 

A Selection of Recommended Resources

Author: Hannah Harvey

Hannah Harvey is an archaeologist and GIS specialist working with CRGIS and the Pennsylvania Archaeological Site Survey.


  1. Hi Hannah,
    I live in Virginia and we have many of these cairns on our land. I would be interested in talking to you about them.

    • Hey, Denise! I’m a full-time archaeologist in WV, but working with a colleague to compile information about rock features in Virginia – hopefully for a comprehensive state survey. If you could message, I will put you in touch with him – since he is local to Virginia.

  2. Are those your photos (mostly)??

  3. Hi Denise,
    Check out

    New England Antiquities Research Association (NEARA) is dedicated to the research of these kinds of stone structures. There are so many stone sites in the northeast and we are always interested in hearing about them outside our area. Send me some pics!

    Teresa Bierce
    NEARA Membership Chair

  4. Would like to talk to our chapter members about this-would you be interested in speaking with our members ? We are digging at the Mouns Jones house in douglassville on wed and sat mornings…this is awesome,never heard of these so close-maybe arrange a walking trip,we are chapter 21/spa members-would like to see this place

  5. Thank you Hannah for a very well written and thoughtful consideration of the potential for significant CSL’s here in Pennsylvania, particularly in the East and Northeast regions. As someone who’s been working in this field of study for over a decade I’m extremely happy to see this level of interest at the PHMC and SHPO. In my opinion these already documented sites and potential sites are an important resource reflecting the true history of our region. While there are plenty of exotic claims, there are also many well recorded features as well as other gems hidden in plain sight. It’s up to the quality of work we field researchers do in concert with open minds such as yours to ensure that these CSL’s are well recorded and taken seriously. So much is here to professionally study and protect.

    I thank you for all your help in my own research and recording of the Alpenglow Rockshelter and Council Rock sites. It’s always been my intention that these sites and this entire mountain will be taken seriously and protected accordingly. Just in these past few months we’ve professionally Lidar scanned a quarter mile in length by several hundred meters in width of features. They’re now tied in and registered with one another and georeferenced to within centimeters. So far this work has been to document the known features as well as investigate the potential for others at the site. Much more has already become visible with the trees and vegetation digitally removed. Full analysis is yet to come. GPR surveys conducted of Alpenglow several months ago are still in process. The level and quality of work are forever increasing, largely due to the growing interest of people like yourself.

    I thank you again for the serious consideration you give to my own work and that of others. The legacy preserved will largely be due to your open-mindedness and willingness to look with clear, unfettered eyes. My sincere thanks!

  6. Great job at summarizing the situation, and I’m thrilled to see something so official acknowledging these structures! Honored to have been included in the recommended reading, as well.

    If there is anything I can do through the CRM firm I work for, my role with the Council for West Virginia Archaeology, or as a private volunteer – I would be thrilled!

  7. Great read. We believe we have a cairn site on our property in Southern Ohio. I have diligently studied these cairns up close and online. It’s very intriguing to say the least. I feel like there is still a lot for me to learn about cairn sites. Thank you so very much for the article and the continued ambition to learn more about them.

  8. Great job Hannah! Thanks to your very well written and highly informative post, I think there will be a lot more open-minded discussion going on, especially among professional archaeologists. You hit all the high points–great summary and great start to what we all hope will be a more comprehensive look at these structures.

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