An old tv show (western?) about a hidden treasure and clues that involved Crosses to find it.

I remember watching an old B & W tv show (western?) that was about a treasure hidden in a cave in the side of a mountain. The cave was sealed off and a structure/house was built in front of it to protect its location . I think a Native American lived in the house to protect it. The plot revolves around a group of treasure hunters looking for this lost treasure unaware that the place they were staying at was actually its location. Clues to the treasures location revolved around I believe Three Crosses. One clue led to the next. The first two were easily solved but he third was the most difficult. It was only solved when one of the treasure hunters, while standing on a hill opposite the house, out stretched his arms while standing I believe inside a rounded rock formation. The sun to his back cast a shadow of his figure exactly onto the house. Can anyone remember the name of this show. I was told that it might have been made into a made for tv movie some time ago in an altered form.