Interesting object ? It reminds me of a few similar objects we have dug occasionally from 1850-1900 era bottle dumps. The objects I am referring to were made of various types of ceramics or pottery, and were usually very crudely made and formed. I do not know what they were used for, but we did dig one once that had the name of a Chemical Works Company out of New York, impressed in the clay before it was fired. Perhaps they were crude ceramic stoppers used to cover vessels containing chemicals while heating them in ovens? I will see if I can find some pictures to better explain what I am referring to. If it was found in a dry creek bed, perhaps it is worn down somewhat from it's original form?