Some archival photos...

[HLin NC]

[DLH17]

#30 white is about to blow someone up. PF

[Welpe]

Are those leather boots with hobnails?

[Forksref]

Officials used to leap off the ground when signaling TD. Also, the wing would signal with a fist (much like punching back a backward pass) toward the EZ that the runner had crossed the GL, then the R would give the TD signal.

[Texas Aggie]

Prior to the stripes, at least in Texas, they wore white long sleeved shirts. They threw red flags. We have a picture of my dad in this uniform around 1960.

[Robert Goodman]

Originally Posted by DLH17

#30 white is about to blow someone up. PF

From the look of it, either his teammate or the official.

[Robert Goodman]

Originally Posted by Forksref

the wing would signal with a fist (much like punching back a backward pass) toward the EZ that the runner had crossed the GL,

And they would "sell" that call with a repeated and/or exaggerated "punch" if it wasn't obvious. I've seen film of such a case (ball crossing plane, runner landing in the field of play) where you could see both wing officials facing infield and swinging their fist from the field-of-play side arm over their head toward the end zone and back, at least twice, like they were mimicking the action of the ball.

Last time I saw this signal was on TV in the Hula Bowl in the 1970s, and the official used an open hand; looked like a rugby ref giving a try.

There's a remnant of this practice in an umpire's fist-with-thumb-up signal.