Originally Posted by IndyKate
I'm confused too - What information tells us he was at Marshall in Raiders?
I thought he was at Barnett through the whole of the movie series until Crystal Skull... Mainly because he's at Barnett in the book "Secret of the Sphinx" (the only one I've read and the only reason I know he ever taught at Barnett) which I think is set in a year near to the events of Raiders... but it's been a few years, so I could be completely off!
He was at Marshall in Raiders. In fact if I'm not mistaken, the establishing shot of the college in Crystal Skull was lifted directly from Raiders.
I think the reason they switched to Barnett in Last Crusade was because for whatever reason they used a different college exterior when filming the movie. I think there is a story related explanation for the switch provided by expanded universe writings, but I wouldn't know it off hand.
Honestly, it wouldn't surprise me if the film makers simply just forgot about the whole Marshall/Barnett thing when making Crystal Skull and just made it Marshall College after re-watching Raiders. It's confusing, but I guess not really important in the long run.