Driveshaft orientation, '72 Duster 4 speed

Hey all,

The driveshaft I saved for my '72 Duster has a 'step' in it like you would see where a pipe is slipped into a larger pipe. Which way does that step go, toward the transmission or the axle? I'm about to put the new U joints in it and I'd like to get it right the first time. And a google image search shows both ways.

TIA