This 9-1/4" shaped plate is impressed with one of Mason's earliest marks "PATENT IRONSTONE CHINA" in a circle, and also has the blue printed mark with Mason's Crown and Banner. It dates c 1813. The pattern is called "Large Vase & Table" by the Mason Collectors Club, and "Vase and Table" in the Coysh book "Blue and White Transfer Ware 1780-1840", published 1970. The plate is shown on page 47 of that book
It is in very good condition, displays well, and rings when tapped. There are utensil marks, a glaze skip (shown in photo 5 on the rock), and a shallow line in the glaze (barely visible in photo 5 at the right tip of the rock).