Absalom’s pillar is a marker for more than one reason. The pillar marked the place where Absalom polled his head, and as such a marker of his own vanity and self-assurance. A monument to Absalom stood in this place (2 furlongs from Jerusalem) according to Josephus [Antiq vii. 10, 3] But more interesting is that Absalom’s pillar marked the location of the king’s dale 2Sam 18:18. This then gives us a firm identification of the location of Abraham’s meeting place with Melchesidec in Gen 14:17.
The valley is further called the valley of Shaveh, heb level ground, or literally made equivalent or like unto. The expression is used in the description of the three friends of Daniel, who were joined by another “like unto” the Elohim. Dan 4 This meeting with Melchesidec was a demonstration of a man who would represent deity. This was to be the shield and very great reward Gen 15:1 that God would provide the mechanism by which the greatest enemy of Abraham would be removed: sin. This becomes part of the exposition of Paul on the man Melchesidec, and the most remarkable care of deity to provide for not only Abraham, but all those who have the same faith as him, a man who could perfectly represent the aspirations of deity in a disposition of holiness, and at the same time a partaker of human nature.
The “tomb” of Absalom was never the burial place of the son of David. He died in the wood of Ephraim and was buried by being covered over by stones 2Sam 18:17. The monument was in fact a Seleucid elaboration of a previous marker for the place of Absalom’s polling, and it became a tradition both to throw stones, and to instruct rebellious children at this place.
The hebrew is interesting. The literal is the “hand” of Absalom, and is translated the hand by both Josephus and the LXX. The hebrew Yad meaning hand, is used of places of memorial. So David would mark the boundaries of his empire at the Euphrates with a Yad or memorial. In fact it is not uncommon for Phoenician burial places to have engraved or sculptured literal hands. (1)
A fourth century inscription has been deciphered written on the sides of this tomb, marked as “This is the tomb of Zachariah, the martyr, the holy priest, the father of John“ The inscription was no doubt made by a crusader who intended to remember the biblical figures, and made the inscription on a famous location near the temple mount.
Look at this detailed panorama: http://gigapan.org/gigapans/fullscreen/81369/
(1)The holy city, historical and topographical and antiquarian notes vol 2 pg 450