Mountain Men Run Into Witches With Tatoos or Birthmarks

by Vic
(Japan)

What is the name of this late 70's or early 80's American movie set in the 19th century?

A group of men are searching for treasure (possibly diamonds) in the mountains. They are wearing 'Little House on the Prarie' style clothes.

They run into a group of pretty girls, who are all demons or witches of some sort, perhaps guarding the treasure and killing men off. Also, women have tattoos or birth marks shaped like a butterfly or angel.

Any ideas?