DAUPHIN ISLAND, Ala. (AP) — Dauphin Island Sea Lab researchers say they believe parts of the oil slick are closer to the northern Gulf coast than previously thought.

Scientist Monty Graham said Friday they found honeycombed chunks of what appear to be crude oil and tar floating in the water about 35 miles south of Dauphin Island, Ala.

Officials from the U.S. Coast Guard and BP PLC say they are investigating the odd discovery. The company and federal agency have said the oil chunks are tar balls, which look like small, rounded pieces of asphalt.

But Graham says the chunks found clearly are not tar balls.

BP operated the oil rig that exploded and sunk on April 20, killing 11 people and spilling thousands of gallons of oil into the Gulf.