MS. Acrey-not just opinion- It may surprise you to know most of the Union dead at Shiloh were buried the exact same way. With the exception of those who died of wounds later or were killed the evening of the first day, who usually had friends or unit members aound to bury them and mark their graves, the battlefield dead were collected and buried over the several days after the battle. They were not'thrown into pits', a burial trench was dug to about the depth of 8 ft, a layer of bodies was laid in the bottom, a layer of dirt on top of them and then a layer of bodies, repeating until the trench is filled 2 or 3 ft from the surface and then the rest filled with soil. This was the standard way of burying battle dead before, during, and after the war right up to WWI(Graves registration units grew out of the need to document the massive cassualties from that war).Records were kept of the number of bodies but
without identification, a list of names was impossible.
After the war the union burial trenches were opened and the dead transferred to the new National Cemetary by the Federal Government. They were checked for some form of identification, those who could be identified were marked, the rest were buried as unknown. The museum at Shiloh contains some of the artifacts recovered at that time. Since no official 'dog tags' were issued during the war by either side, this depended on the deceased making sure they had some form of ID that survived the years before reburial. The government at the time felt no obligation to do the same for those they considered as rebels and left it up to the individual southern states to reclaim their dead if they chose. Most chose not to bear the expense.

Admittedly, battlefield inhumation was sometime a little slipshod and hurried, but by the time anyone had the leisure to bury dead at Shiloh, some had been laying out in the sun for several days. Think of the last time you walked past a several day dead large animal or meat that had gone ripe from too many days in the frig and magnify that by hundreds of times.The unlucky guys who got to do the burying hurried as fast as possible for obvious reasons. But disrespect was not the driving force for the mode of burial.