Hi Colin,
In overall appearance, the design on your olla seems to resemble Casas Grandes (Ramos Polychrome) pottery, but even though the shape and clay (color) are atypical, the design seems to speak to a Hopi, or possibly Santo Domingo origin IMO.
However, I am no altogether sure... I'll look through some old Indian auction catalogs and let you if I can give you a more definitive answer.
Regarding the item I posted above, I am attaching another photo below, which contains a rather revealing clue as to the object's purpose...
Cheers,
Chris