Hi Neighbour....(me from Canada)
AND WELCOME TO THE BOARD..There are no marks of any sort on the bottom, or maybe peek along the side....just a wild guess. Is it red clay looking on the bottom....
It may be tough for me to identify, but the others here know much more than me. Positive no marks of any sort on bottom...
Maybe a clearer photo (if possible) of bottom...
In the meantime - I pulled up 38 pages (1,126 images here) on this site of American Pottery examples here, as I am just assuming that a pix here (might) help to narrow things down. Take a look through these, and see if you spot something similar.
I TOO, will have a look there, BUT I have to run out to the store here......so I will peek a bit later OK, but for now enjoy browsing through here, and maybe we can get a lead...
http://search.rubylane.com/search?ss=american+pottery&hsb=Find+an+Item and again WELCOME.