I was fighting a dragon in Winterhold and mauled it after it landed at the entrance of the town, so the skeleton was lying there, right?

Some time afterwards, I do the Saarthal quest for the College. After I finished there, I fast-traveled to the college, and somehow, the dragon skeleton glitched from the entrance of the town to the archway entry to the front courtyard to the college. After I did my business inside, I go back out and find that the skeleton glitched under the friggin' bridge into Oblivion. /pun

Here's a pic of it in the archway:

http://img100.imageshack.us/img100/5908/dscn0890v.jpg