Edward W Ludwig's "The Lonely Ones" (short story, first contact, free): Stone age man is modern man what modern man is to...
Fact sheet.First published: Galaxy or If, July 1953.
Note: Project Gutenberg's HTML copy includes image of If's cover with the story, but attributes the story to Galaxy. ISFDB attributes it to If.
Download full text from Project Gutenberg.
Related: Stories of Edward W Ludwig; first contact fiction.