Friday, February 8, 2013

Lehigh County

This week our journey by county through the archaeology of Pennsylvania takes us to eastern Pennsylvania and Lehigh County. This county is mainly situated in the Great Valley section of the Ridge and Valley province with a small section of the New England province in the southern part of the county. The Lehigh River is the main drainage that eventually empties into the Delaware River. The major streams are the Little Lehigh and Jordan creeks. The Great Valley zone is largely a rolling terrain with small streams.  This is reflected in site locations with only 40% of the sites in riverine settings. The main lithic resource is jasper with 34% of the sites producing artifacts of that material. Chert is the second most common toolstone with 30% of the sites producing that material. Both jasper and chert are found in local bedrock formations.

The county has a moderate density of archaeological sites but only a few have been tested and these generally were surface collections rather than deep excavations. The largest excavations and most extensive research has been conducted at the jasper quarries and their associated workshop areas. Jasper is a micro-cryptocrystalline rock with a high silica content. It is a type of chert that contains small amounts of iron that gives it a brown or yellow color. Jasper turns red when exposed to heat but is usually not found that way naturally. Less commonly found examples are black or green. The jaspers of eastern Pennsylvania are located in the Reading Prong section of the New England Province and they are associated with the Hardyston formation which mainly consists of sandstone and quartzites.  They are found at the contact between the Hardyston quartzite and the adjacent schist formation. In the Reading Prong, jasper is actually a sedimentary rock formed by a process called replacement. Over millions of years, silica from the Hardyston formation precipitated into voids in the schist forming large pockets of jasper.

Fluted points made of jasper

Jasper is an easily flaked toolstone with a very durable edge. It was extensively used by the prehistoric peoples of the region, as early as the Paleoindian period, over 11,000 years ago. Twenty-five percent of all fluted points in Pennsylvania are made of this mateial.  The Transitional period (4,300-2,700 years ago) probably experienced the most intensive use of this material, especially in the production of Lehigh and Perkiomen broadspears, scrapers, drills and other tools. During this time it was also traded throughout the Middle Atlantic region, from Virginia to Vermont.

Jasper broadspears

In 1891 and 1892, Henry Mercer (1894) conducted the initial investigations of the Hardyston formation and documented ten jasper quarries in Lehigh (6), Berks (3) and Bucks counties (1).  He focused his work on the largest quarries located near the communities of Vera Cruz and Macungie in Lehigh County.  Here, he found these sites littered with layers of jasper flakes and the landscape pock-marked with 60 to over 100 prehistoric mining pits over areas of six to ten acres.  Roland Hill reported in 1938 that the 140 pits at Vera Cruz, were from ten to thirty-five feet deep and ten to one hundred feet across. Mercer and some of his informants tested several of these to depths in excess of 30 feet and concluded that the prehistoric miners first removed jasper in near-surface context and then, as needed, began to dig deeper, gradually enlarging the excavations outward and downward. One of his informants reported putting shafts to 40 feet in a crater with a 100-foot diameter. At several sites, they found stone diggings tools buried in the pits. Mercer’s maps and publications introduced these sites into the archaeological literature and represented the foremost work on the quarries for nearly a century. 

Quarry profile - notice the sloping layers of jasper flakes. 

            In the 1980’s, Professor James W. Hatch of the Pennsylvania State University conducted extensive surveys of the region in advance of the I-78 highway project. He documented numerous quarries and quarry related workshop areas. Anthony and Roberts (1988) followed up on this work and developed the Hardyston Jasper Prehistoric Archaeological District. Anthony and Roberts (1988) tested numerous workshop sites but none of the actual quarries. The district includes both quarry and non-quarry related sites and is identified by sites with predominantly jasper artifacts.  Spanning a great deal of time, it includes sites from Paleoindian through Late Woodland times tracing the changing use of jasper mining and tool technology. The Hardyston Jasper Prehistoric Archaeological District serves as a historic preservation management tool for this important resource.

James Hatch continued his research on the quarries and related workshop sites in the 1980’s and 90’s. Hatch was concerned with documenting how the quarries were used, the distribution of the mined jasper, and developing sourcing signatures.  Chemically, he mapped six of these quarries in detail: Vera Cruz, Mast Farm, King’s, Urffer’ Farm, Lyons and Longswamp (the latter two are in Berks county). He could not map Macungie, Leinbach’s Mills, Frankenfield or Durham due to 20th century development. He conducted limited controlled surface collections at Vera Cruz, Lyons and Kings quarries and, at Vera Cruz, he  hand-excavated quarry pits and mapped deep backhoe profiles through some of the pits. 

            His work at Vera Cruz was especially instrumental in documenting the overlapping sequence of pits used by Native Americans to extract the jasper. At the quarry, once the blocks of high quality material were exposed, the low grade cortex was removed and other impurities were flaked away. Generally, the blocks were reduced to a transportable size. Some tools were finished at the quarry but most of this work was accomplished elsewhere. There are numerous workshop sites around the quarries documenting the final production of jasper stone tools.

            The work undertaken by the PHMC at the King’s quarry site (36Lh2) in 2002 added to our understanding of the prehistoric mining process. After conducting two controlled surface collections, recovering over 50,000 artifacts, a backhoe was used to cut a profile through the quarry pits. Here, an 85 foot wide, 23 foot deep pit was uncovered with several smaller pits located along the parameter. This confirmed Hatch’s work, although the King’s quarry pit was nearly three times the size of anything at Vera Cruz. Carbon 14 dates were obtained from the Kings quarry excavation and the investigators were able to date the various stages of infilling. Based on these dates, the maximum depth was probably reached during the Transitional period and the pit began to naturally backfill in stages up through the Late Woodland period.

            Large Profile of Vera Cruz

Hatch’s most significant contribution was the “sourcing” research he conducted with Adam King and Barry Sheetz of the Material Science Laboratory at Penn State. Jasper is found as artifacts from New England to North Carolina.  Major quarries are located near State College in central Pennsylvania; in the northern Shenandoah Valley of Virginia; in northern Delaware as well as eastern Pennsylvania. There are some visual differences between the material from these quarries but they are all similar in appearance. In order to better understand trading patterns and to define territorial boundaries, it is important to know which quarry produced the artifacts from a particular site. Using geochemical analyses, such as neutron activation and X-ray Fluorescence spectroscopy to detect trace elements within the jasper, Hatch and colleagues were able to distinguish each of the main quarry areas from one another, but not the individual quarries within the entire Reading Prong. Contrary to popular opinion among archaeologists, his results showed that the Reading Prong jasper was not regularly moving outside the Middle Atlantic region to New England or the Southeast. The material from these four quarries rarely moved more than 200 miles. In addition, he found that many of the artifact samples he tested did not originate from the four main quarry areas, suggesting there were additional sources that have yet to be discovered.

            Finally, James Miller reported the quarry sites rarely produce any pottery. We checked our files and there is only one recorded pottery shard in the collection of the State Museum and based on the GIS files, there is only one site (36Lh19) in the county that has produced pottery (Late Woodland). There are many possible explanations but it is curious that Woodland habitation sites seem to be rare in an area so rich in lithic sources.

           In a letter to the editor of the Pennsylvania Archaeologist (1938), Roland B. Hill felt these quarries were so important that the state or federal government should restore and preserve the Vera Cruz quarry. That did not happen but Lehigh county purchased several acres and it is open to the public today.

We hope you have enjoyed this glimpse into the archaeological heritage of Lehigh County. Hopefully it will inspire you to seek such publications as Indian Jasper Quarries in the Lehigh Hills by Mercer or any of the journal articles on archaeology conducted in Lehigh County and published in Pennsylvania Archaeologist.  Understanding and exploring our archaeological heritage is pivotal to our understanding of human behavior and our ability to change and adapt over time- just as the peoples of Lehigh County have done for thousands of years.

Anthony, David W., and Daniel G. Roberts
1988    Stone Quarries and Human Occupations in the Hardyston Jasper Prehistoric District of Eastern Pennsylvania.  Submitted U.S. Department of Transportation, Federal Highway Administration, and Pennsylvania Department of Transportation Engineering District 5-0.

Hatch, James W.
1993    Research into the Prehistoric Quarries of Bucks, Lehigh and Berks Counties, Pennsylvania.  Submitted to the Pennsylvania Historical and Museum Commission, Harrisburg.

Hatch, James W., and Patricia E. Miller
1985    Procurement, Tool Production, and Sourcing Research at the Vera Cruz Jasper Quarry in Pennsylvania.  Journal of Field Archaeology 12:219-230.

Hill, James S.
1954    Jasper Quarries of Macungie Pennsylvania Archaeologist 24(1) 20-21.

Hill, Roland B.
1938    A Visit to the Jasper Quarries. Pennsylvania Archaeologist 8(1): 65-66.

King, Adam, James W. Hatch and Barry E. Scheetz
1997    The Chemical Composition of Jasper Artifacts from New England and the Middle Atlantic: Implications for the Prehistoric Exchange of “Pennsylvania Jasper”. Journal of Archaeological Science 24: 793-812.
Mercer, Henry C.
1894    Indian Jasper Mines in the Lehigh Hills.  American Anthropologist 24(1):20-21. 

For more information, visit or the Hall of Anthropology and Archaeology at The State Museum of Pennsylvania .

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