In this October 2012 file image from video provided by David J. Ruck are timbers protruding from the bottom of Lake Michigan that were discovered by Steve Libert, head of Great Lakes Exploration Group, in 2001. On Saturday, Aug. 24, 2013, Libert's crew will haul the massive tumber to the radiology section of a Gaylord, Mich., hospital for a CT scan hoping to determining the age of the tree that produced it and when it was cut down. Libert thinks the beam could be the bowsprit from the Griffin, a long-lost ship commanded by legendary French explorer La Salle, which he has sought for 30 years. (AP Photo/David J. Ruck )

Explorers who removed a wooden slab from Lake Michigan this summer are taking an unusual step to determine whether it could have come from the Griffin, a long-lost vessel from the 17th century.

The nearly 20-foot-long timber will undergo a CT scan Saturday at Otsego Memorial Hospital in Gaylord.

The scan will produce images of the beam's interior, including tree rings. An expert with Cornell University in New York hopes to analyze the ring patterns and estimate the timber's age and when it was cut down.

The Griffin was commanded by French explorer La Salle and disappeared in 1679.

In this June 15, 2013 file photo is explorer Steve Libert on a fishing boat as dive teams prepare to inspect a site in northern Lake Michigan. Libert, who has searched 30 years for the French explorer La Salle's lost ship the Griffin, hauled a nearly 400-pound beam ashore in June. On Saturday, Aug. 24, 2013, Libert's crew will take the massive tumber to the radiology section of a Gaylord, Mich., hospital for a CT scan hoping to determining the age of the tree that produced it and when it was cut down. Libert says if the wooden beam dates from that period of the long-lost vessel, it probably came from the Griffin. (AP Photo/John Flesher, File)

Expedition leader Steve Libert says if the wooden beam dates from that period, it probably came from the Griffin. State officials say they're not convinced it's from a ship.

Explore further Wooden beam could be detached part of shipwreck

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