When the corner of Fifth Avenue and Market Street became a hole in the ground for the construction of Three PNC Plaza in 2007, archaeologist Christine Davis grabbed the opportunity to uncover artifacts that had long been buried.
She found 26,000 -- from a small statue of a Civil War general to saucers from a mid-19th-century tea room. Guests of the Fairmont Pittsburgh hotel, located in the finished PNC tower Downtown, can now see a display of items that were beneath the ground under their feet for more than a century.
But at most construction sites in Pittsburgh, the buried remnants of earlier times remain a mystery.
State and federal laws require archaeological investigation of development sites only when government money is involved or when certain permits, such as those needed to disturb particular environmental sites, are necessary. Even when public money is involved, the state's Bureau for Historic Preservation has no regulatory powers. It can advise whether a site has potential for finds, but it has no power to enforce its recommendation.
"We're happy with the projects there are but there are times when we think, 'I wish we could do more,' " said Ms. Davis, who is president of Christine Davis Consultants, a Verona firm that specializes in urban archaeology.
She said as she watches private construction projects proceed without archaeological review, she thinks of what she might be missing, but then realizes, "You just have to let it go."
When discoveries are made, landowners have the right to keep the artifacts, but they usually decide to donate the items to the State Museum of Pennsylvania in Harrisburg, which is the easiest option to ensure items are cared for properly. The museum took in 6,128 archaeological artifacts from around the state last year.
Another option is donating to a university. Artifacts from the 1997 construction of the Lazarus department store Downtown are now used as teaching aids at California University of Pennsylvania. The items include medicine bottles from a 19th-century pharmacy that provide a window into the medical practice of the time.
PNC decided to keep its artifacts. About 250 of Ms. Davis' most interesting finds from that project, which was a private development, are on display in the Fairmont. The rest went to the PNC Legacy project, the company's preservation program, which usually conserves artifacts from old banks.
Ms. Davis is now in the early stages of doing the same work on the construction site of the company's new tower at Fifth and Wood. PNC's decision to invite an archaeological survey of both projects is rare.
"Most people don't really go any further with archaeology if they're not required to," said Kira Heinrich, historic preservation specialist at the state Bureau for Historic Preservation.
Ben Resnick, an archaeologist and senior director with GAI Consultants, an engineering and archaeological firm with offices in Homestead, points to examples such as city ordinances in New York City and Alexandria, Va., as models for stricter protections of historical artifacts.
Alexandria's protections were the first of their kind in the country when they passed in 1989. They require private projects to determine if a building site could be of archaeological significance and take reasonable protective measures if it is.
Even under Pennsylvania law, which Ms. Heinrich describes as "fairly weak," the Bureau for Historic Preservation comments on the potential archaeological significance of between 2,500 and 3,000 new projects every year. Three quarters of those are deemed to have little potential, and an unknown percentage of developers of the remainder choose to hire a firm to investigate more.
When there is an investigation, time pressure can be a problem. Jason Vendetti, vice president of the archaeological firm A.D. Marble & Co., which is based in the Philadelphia suburbs but has offices in Pittsburgh and across the state, said PennDOT is usually deferential to archaeological work on its projects. However, when private developers are forced to do an investigation, typically because of environmental impacts, they can be impatient.
"On the private developer side, often they get a letter from the state museum office saying, 'You need to do a study,' " Mr. Vendetti said. "In that case there's always pressure to get the work done on time."
Ms. Davis keeps a hard hat and work boots in her office at all times. When contractors call and say they might have found something, she is usually on the scene in minutes, then works during lunch breaks or evenings.
"They give us as much time as they possibly can," she said. "We'll work odd hours so that we're not in their way."
In the rare case of a private landowner deciding to do an investigation, disappointment can ensue.
"Every once in a while a landowner is curious," Mr. Vendetti said. "A lot of times the landowner thinks they're going to get a lot of cool arrowheads or something and that's usually not the case."
But items of no interest to regular citizens can be of great interest to archaeologists. For example, fragments from arrowheads can indicate the technology and methods for making the weapon at the time, Ms. Heinrich said.
Most of the artifacts donated to the state museum are interesting because of what they show about their surrounding societies, not in and of themselves. Bricks found during a dam project in Leetsdale last year, for example, shed light on the technology of a 19th-century religious group called the Harmonists.
"It's not about getting stuff for our collection," said state museum spokesman Howard Pollman. "We have 5 million things in our collection. It's about getting a better understanding of Pennsylvania's past."
Occasionally, there are far more dramatic findings. During the North Shore Connector project, for example, researchers in 2008 found Native American arrow points and one of the largest collections of toys ever discovered. Some of the artifacts were under just a few inches of soil.
Peter Sullivan: email@example.com or 412-263-1939.