Wall dates to 1824, at least.

When about 40 feet of a retaining wall gave way near Jackson Street a week ago today, the reason was clear: More than 6 inches of rain had fallen.

What is less clear and more interesting is the history being revealed.

The Z-shaped wall that runs from the corner of Monroe and Jackson streets forms a dividing line between the Warren County Board of Supervisors’ office building and Vicksburg Auditorium. It then forms a barrier behind various buildings along Cherry up to Main Street.

Officials with the county engineering firm, ABMB Engineers Inc., and a few supervisors decided to do a little digging, not in the mud that surrounded the fallen wall but in the files of land records kept in the courthouse.

It is believed the wall dates to the 1800s, although a land survey document from 1824 only describes how the block was laid out, Rhea Fuller of ABMB said.

&#8220I’m sure the wall dates to at least that time,” Fuller said. &#8220But there’s no way of knowing for sure.”

Vicksburg proper was chartered in 1825 as a city on hills sloping down to the Mississippi River. The area, just northwest of the Warren County Courthouse, was in the original survey.

Another survey from the 1800s gave some evidence of tunnels or other type of structure in the area where the wall is today.

Warren County’s engineering firm began assessing all options Monday to stabilize and repair the wall.

Those assessments included soil borings to test the integrity of the support system beneath it. Without work, the county building would eventually wash down the hill – which is why a wall was likely erected to preserve the lot in the first place.

&#8220The earth must be secured below the county office’s slab,” Brian Robbins of ABMB Engineers Inc. said. Supervisors declared an emergency to allow the firm to take all measures in repairing the brick-and-mortar structure.

Ownership of the wall between city and county property had not been determined, as it forms the property line there. Robbins said Monday no cost estimate was available for the complete repair of the wall, but theorized the replacement of stabilizing support structures underground would run the county about $16,000.

ABMB will consult with geotechnical firms Burns Cooley and Dennis and Structural Solutions LLC to gather cost and work estimates.

Crews from the city Public Works Department worked to clean up fallen brick from around the auditorium’s huge 125-ton chiller system and to repair pipes near the system that were perforated when the huge chunk of wall fell.

Mayor Laurence Leyens said the city’s share of the cost would be determined as the work continues, with the bulk of the cost being &#8220in relation to stabilizing the Board of Supervisors’ building,” he said.

District 5 Supervisor Richard George called it &#8220a mutual problem” because of its importance to important functions, including the auditorium’s site as a voting precinct.

Two events were moved from the auditorium to the Vicksburg Convention Center due to the work, Gospel Crusade, a three-day spiritual music concert scheduled to begin Wednesday and a TRIAD senior citizen luncheon set for Wednesday.