Isaac Davis operated out of the Trenton Pottery Co. factory from 1872-1879.  Although the text "T. Pottery Works" is shown below the coat of arms, the center of the sheild contains the initials "I." and "D." This was a common way Isaac Davis marked his pieces.  Therefore, we can conclude that this was made during that time period at the Trenton Pottery Co. during Isaac Davis' tenure there.