Can't Remember/Find Manga With Prehistoric Girl In Modern Japan

[DracoSafarius]

Randomly remembered a manga I'd come across a chapter of a long time ago, and have been trying to find it since then, but no luck. From what I can remember of the chapter I read, there's a neanderthal/cavegirl in Japan's modern times, and she's got feelings for the MC who's just a regular old Middle/High school student. There's another girl who I cannot really remember anything about but she counsels MC on actually confessing to the cavegirl. Really vague, and probably not all too good a description, I know, but I'm having absolutely no luck.

From what my friend and I have found through searching so far, it's not Nadenade Shikoshiko, Neolith Girl, or Googookaka.
Really, if you've ever read a manga with a prehistoric girl as a love interest for the MC I'd appreciate it if you throw the name or link below.