Driveshaft on my 66 valiant fell off. Now what?

Thanks for all the quick replies. Ya, you are right, it probably wasn't useable, but at least i'd have the yoke.

Right now i'm stuck with nothing. Its sunday so tomorrow i will be calling around to every junkyard. Its a 7.25 rear end. I will get under the car tomorrow with a tape measure and get you that dimension.

If you have one, that would save my day.

Edit: Its just a slip in yoke. (I think thats what you were asking, supershafts)