Iron boss and grip of a shield

Shield boss, height 13cm, diam 13cm. Tall convex cone, with short spike on top and narrow flange around bottom; very slight carination above vertical waist. Flange only 1.3cm wide, and iron rivets holding boss to shield have small stud heads. Only 1 rivet survives since flange almost entirely broken away. Faussett notes the height as 5 3/8 inch tall, 5 1/4 inch diam., and observes it to be by far the largest he has met with.