When I was a kid I had access to a handful of "golden age" SF mags, out of which a couple of stories stick in my mind.
One of them started with a caveman returning from foraging with his companions, and demonstrating altruism by giving a branch covered with berries to the girl unable to fend for herself due to a broken back.
He later meets two (?) spacesuited individuals, who communicate with him using "tubes": there was an illustration which showed these as hoses attached to the suits rather than as handheld instruments or what we British would call "valves" **
Towards the end of the story he fights the pack leader, and then leaves carrying the girl with the broken back: the implication being that they were the ultimate ancestors of the Human Race.
Was this one of the published variants of Clarke's "Encounter at Dawn", something well-known by some other author, or simply a tale which has vanished into the mists over the seventy years or so since it was written?
** I think it's fair to contrast the author's casual mention of "tubes" in this story with the far more cautious approach taken by Adams in "Watership Down".
Possible cross-reference to "Pulp era" story: "Dachwu, remember?" which identifies one of the magazines as Super Science Stories, April 1949... unfortunately the USA edition at archive.org doesn't also contain this story although there is a possibility that the British one did if that's what I saw.