My Grandmother's (and I am 60) old two toned pottery dishes & large serving dishes

I love these dishes as they have been in our Family for years. My grandmother use to make lunch and dinner for all of there farm workers, these dishes are very heavy,and sturdy...however, I do not wash them in the dishwasher..I have several very large serving bowls with lids some with handles like the little dishes in the pictures as well as other large platters. My Grandmother would be at least 105 yrs old so I assume these dishes are at least 80 yrs old. There does npt seem to be any name on the bottom.
Does anyone know anything about these dishes? If so, please let me know. I have not be able to find out any history on them or who made them.
Thank you in advance.

Linda Coelho