[going hot]

Most likely they were ingesting peyote buttons for the mescaline. The wild tobacco growing there is most likely because that is where wild tobacco grow.

The datura "hallucinogens" are atropine, and it's natural derivatives. Some hallucinogen all right. Get that heart pumping right out of your chest.

[ifinnegan]

I think scopolamine is the major chemical in datura above and beyond the atropine also present.

[JimSEA]

I was wondering about Jimson Weed known in the southwest and Mexico as locoweed and para loco respectively.