The Mason Dixon Line was a bit blurred out here. Allegiances were divided and fluid.    On Pea Ridge Battlefield, Confederate and Federal armies faced off to determine the fate of Missouri; be it Union or Confederate?   The Union prevailed but as in so many other fields not until many had died on both sides. Only two simple monuments stand here: An obelisk that recognizes Confederate lives lost in 1862 and a granite angel placed jointly by surviving Union and Confederate Soldiers to remember all who have served.