What does the crescent moon on Gettysburg gravestones mean?

Currently, military cemetaries use a crescent moon for Moslem soldiers.

https://web.archive.org/web/20101124043043/http://www.nps.gov/archive/gett/GETTKIDZ/cemetery.htm

"Today, the Soldiers National Cemetery is called the Gettysburg National Cemetery. The cemetery holds the graves of honored dead from all of America's major wars and is marked with passages of the touching poem "Bivouac of the Dead" by Theodore O'Hara."

This (crescent moon) is the emblem of the Union Army 1st Division (XI Corps, 11th Army). The Corp arrived at Gettysburg on July 1,1863, hoping to restore its reputation from Chancellorsville. With the collapse of the its right flank, the Corps was forced to retreat through the town of Gettysburg to Cemetery Hill. The following day, the Corps successfully defended East Cemetery Hill. The Corps reportedly had 10,576 officers and men prior to the Battle of Gettysburg; of the less than 9,000 men who engaged in battle, 368 were killed, 1,922 were wounded and 1,511 were captured or missing for total of 3,801.

https://en.wikipedia.org/wiki/XI_Corps

There is also a monument at the location where the 119th New York Infantry Volunteer Regiment stood with 11th Army north of Gettysburg. The monument was constructed by the State of New York and bears the State Seal of New York and the crescent moon, a symbol of the 11th Army, in which the fought.

russscott.com/~rscott/119thny/119thnyn.htm no longer exists