Societies with matriarchal lines of descent are few and far between, but they do exist. Truly matriarchal societies, however, are incredibly rare to the point of nonexistance, and tend to occur only under insanely specialized conditions, if at all--even the few Native American societies held up as "matriarchal" usually have male chiefs and all-male religious traditions, which doesn't sound like a feminist dreamworld to me. There is absolutely no concrete evidence of a widespread prehistoric matriarchy that can't be explained in several dozen other, much more plausible ways. This is not to say that women are inherently subservient (and I will pummel anyone who says it is!) but one's desire to promote one's belief in sexual equality is absolutely, positively, under no circumstance, excuse for sloppy, romanticized science.
Really, I don't usually rant about such things with quite such frequency--most of my life is a relatively staid world of chunky tapirs and working out Art Deco cyberspace sigils. I think my moral and ethical buttons are just getting pushed repeatedly this week. I blame sunspots.