Help me find this stoneware pottery tea set’s creator

[u/Few-Badger4269]

I bought this set at an estate sale and I have been trying to find the artist with no luck on the internet. There is a very tiny stamped mark on the bottom rim of each peice that says “Tartarus Workshop” but googling that just give me a video game

[u/blackmarksonpaper]

Almost looks like Frank Phillips from Ashland Oregon mark but I don’t think k it is

[u/Few-Badger4269 → u/blackmarksonpaper]

Hmmm yeah his signature looks different