Possible Native American Basket unusual base stand.

I bought a number of what I think maybe authentic Native American baskets at an estate sale that also had Navajo weavings. I do not know really anything about how to determine if these are actually Native American. The basket is a tight weave with a kinda step pattern on the interior. Also I think unusual base and the basket is very sturdy and does not "bend" like other likely Navajo baskets. nicely made and would like to get any information / opinions from others. In any case and information would be greatly appreciated. Thanks much.