Jack Bolton's dead body is located in a wyvern nest which is on a rock platform near Camp Freedom (west of the Mysterious Cave) in the Orobas Fjords. If you search his corpse you can loot a scroll and a piece of the seal (required for the quest Grave Robbers), along with Hunter Gauntlets (part of the Hunter armor set).
|“|| The crumpled note contains a cryptic message:|
Enclosed you find one fourth of a seal, part of a pathway to treasure unreal.
Find the tomb in the Orobas Fjords, where buried lies a warlord's hoards.
Three others will wait to unite the key. Do all this and rich you will be.