OXFORD – Decades after it disappeared, a stone marker honoring the Maine infantry unit that turned the tide at the Battle of Gettysburg is finally being replaced.

About a dozen Mainers headed to Pennsylvania to gather on Little Round Top, the hill where Col. Joshua Chamberlain’s 20th Maine Infantry mounted its famous charge 138 years ago to the date.

The Maine contingent planned to begin the ceremony Monday with a salute to the flag, a prayer and a rendition of “Battle Hymn of the Republic.”

After historian Ed Bearss spoke about the 20th Infantry’s Civil War exploits, a new stone marker honoring the unit’s left flank was to be unveiled.

Leslie Dean, department president of the 170-member Maine Daughters of Union Veterans of the Civil War, led the Maine contingent.

“We are doing the job,” Dean said before her departure from Maine. “We raised the money, are going to perform the dedication ceremony and are even taking the stone back.

“In all likelihood this will be the last monument placed at Gettysburg. A moratorium has been placed on installing any new markers.”

The original marker disappeared between 1930 and 1960. The replacement will be placed in a piney area on the small rounded hill that lies toward the south end of where the heart of the three-day battle was fought.

There is a marker on the fields for every regiment that fought in the Battle of Gettysburg, Dean said. A total of 15 units from Maine, made up of 5,012 enlisted men and 330 officers, fought there, she said.

To preserve the memory of the 20th Maine, the Maine Daughters of Union Veterans of the Civil War hired David C. Pratt, owner of Bolster Monumental Works in Oxford, to duplicate the original stone.

The 20th Maine had two stones, each placed to honor a flank of the regiment.

To duplicate the missing left flank stone, the remaining stone was “rubbed” and that image sent to Pratt, who could match the exact size and style of the lettering. Rubbings are made by placing paper over the design or words to be copied and then rubbing it with black wax.

The inscription “20th ME. INFY, July 2, R” was engraved into the stone on three lines Friday afternoon. The stone is 12 inches by 18 inches by 24 inches, and Pratt estimated it weighs 300 pounds.

The group wanted the stone to come from a Maine quarry and be engraved by a Maine craftsperson. However, Pratt said he had to settle for Vermont granite because he could not find a piece from Maine to match the one at Gettysburg.

“Maine granite has too much mica in it, and it doesn’t hold a polish,” he said.

Little Round Top is to the left of where the main Union line mounted its famous charge.

“That’s where Colonel Joshua L. Chamberlain had everybody fix their bayonets and charge the troops from Alabama,” Dean said. “The common thought is that if he had not charged, the fellows from Alabama would have come over the hill and changed the course of the battle.”