My father took me to see a western back when I was a kid. AS I REMEMBER, the movie setting was in the northwest or northern plains. All I can remember was the end of the movie. There was a small group of cavalrymen that lined up to charge a very large group of indians (I believe Sioux) across a large expanse of open ground while a few non-combatants hid up above the fray. Of course all the cavalrymen were killed against such overwhelming odds. Right at the end, a cavalryman's small dog stood over his master's body. Movie was in beautiful color (Cinemascope?). Please help me find this movie......I've been searching for it for many years.