Archaeologists have uncovered an 18th century cemetery believed to have serviced the French Fort Rosalie — the earliest known settlement on the Mississippi River.

The discovery was announced Thursday night at a lecture at the Grand Village of the Natchez Indians as Mississippi Archaeology Week came to a close.

Thurston Hahn, a historical archaeologist with Coastal Environments, Inc., said dig crews have been conducting &uot;shovel tests&uot; on the grounds of the historic house, Rosalie, for almost two years.

The studies were commissioned by the U.S. Army Corps of Engineers as part of the ongoing Natchez Bluff Stabilization Project.

&uot;In this particular area we were intrigued, because every shovel test was different,&uot; Hahn said.

Archaeologists believe the strata’s incongruities are the result of the construction and subsequent demolition of a cotton compress on the site years after the cemetery had been abandoned.

Constructed in 1716 by French settlers, Fort Rosalie was virtually destroyed in a Natchez Indian uprising in 1729.

At least six crude maps dating from that time period show a cemetery at the foot of the hill on which the fort then stood. The hill was shorn down to construct the cotton compress around 1870.

Hahn said 25 burial pits have been uncovered along the bluff between the Rosalie gazebo and the mansion itself, which was built in 1824.

When crews first stumbled upon the burial pits this summer, they assumed the dark, rectangular &uot;stains,&uot; created by rotting wooden caskets, were part of the cotton compress foundations.

But, that theory was quickly ruled out by the absence of historical trash, Hahn said.

&uot;We sat out in the sun for about an hour trying to figure out what we were looking at,&uot; Hahn said.

Once archaeologists placed a compass parallel to the stains, they realized they were facing east to west, a feature characteristic of cemeteries.

Since then, the team has uncovered many more stains, some of which are shaped exactly like the &uot;toe-pincher&uot; coffins that created them.

Most of the burial pits are clustered, but one outlying stain had archaeologists intrigued.

Hahn said the grave probably belonged to a settler not of the Catholic faith — the predominant religion of the day — or one who had committed a sin too great to be buried alongside fellow Catholics.

Further excavation of one burial pit uncovered the brass buttons of the deceased’s clothing. Hahn said the buttons are arranged to form the characteristic &uot;French fly.&uot; Other buttons suggest a cape and waistcoat — dress customary of French military officers.

Archaeologists feared the foundations of the cotton compress had severed one grave near the bluff’s edge, but they soon realized the casket was shorter because it was that of an infant – probably one or two years of age.

It was this grave that archaeologists have been forced to exhume to allow the corps to construct a drain as part of bluff stabilization.

&uot;The only graves we’re going to exhume are those that will be impacted by the corps’ construction,&uot; Hahn said, adding that the drain is critical to the bluff stabilization’s success.

Those graves that are exhumed will be transported to Louisiana State University where scientists will collect as much information as possible.

Hahn said the dig is now complete and archaeological crews will clear the Rosalie site today in preparation for the Great Mississippi Balloon Race.