Archaeologists are fanning out to assess the spill's effect. The Gulf shoreline is chock full of history and to a trained eye, the bounty springs out.
"This is like Christmas Day for me," said Courtney Cloy, an archaeologist mapping the Timbalier Islands, a barrier island chain on Louisiana's central coast. "I am finding ceramics all over the surface out here."
The origin of the ceramics was unclear. Perhaps they washed in from a shipwreck just offshore. Or they might have come from a hotel or home that once stood on the badly eroded barrier islands.
For now, the Timbalier islands are safe: Oil contamination has been modest and cleanup crews are being kept at bay.
But archaeologists have grave concerns for other locations.
Oil has begun washing up on Pensacola's beaches, where in 1886, Geronimo, the Apache warrior, was imprisoned in Fort Pickens, the largest of four forts built to defend Pensacola Bay.
On the Mississippi coast, Ship Island was the only deep-water harbor between Mobile Bay and the Mississippi River for 300 years; thousands of Europeans first set foot in North America there, earning the nickname Plymouth Rock of the Gulf Coast.
During the Civil War, Ship Island was Union Adm. David Farragut's base of operations, where he successfully launched an attack on New Orleans in April 1862.
On Grand Terre Island, just west of the Mississippi River, archaeologists have found remnants of a colony set up by Jean Lafitte, the pirate who helped Andrew Jackson win the Battle of New Orleans.
Archaeologist hope to avoid the mistakes made during the Exxon Valdez cleanup.
"We learned from Exxon Valdez that there were incidents of looting by cleanup workers, equipment being brought in, destroying the ground," said John Rawls, marine archaeologist with Earth Search Inc., a firm hired by BP to do archaeological surveys.
In one incident, cleanup workers stumbled across a prehistoric Chugachmiut burial cave containing wooden artifacts.
"Cleanup workers found the cave, which was unknown to archaeologists, and removed some of the bones and then called a supervisor," McMahan said. He said Exxon security collected more of the bones and state troopers raked remains into a body bag and carted them away. "The site was pretty much trashed," he said.
McMahan said cleanup workers need to be trained to be aware of their surroundings and to tread lightly on the landscape.
Archaeologists worry the push to clean the BP spill as fast as possible is causing damage. Bulldozers and dredges are being used to build barrier islands and erect sand dams, and thousands of workers are raking tar balls and crude off beaches.
"Avoidance is No. 1," Cloy said. "We want to keep our footprint on these sites as minimal as possible."
On The Web:
Minerals Management Service's Web site for Gulf shipwrecks:
Alaska Office of History & Archaeology Web site on Exxon Valdez: