2 1/4" X 2 5/8" (56mm X 66mm)

(Crown incuse) "T in a circle"

 {Maker unknown}

Picture courtesy Earnest Griffin

2 1/4" X 2 3/4" (56mm X 69mm)

(Crown inkstamp)

 {Tver Porcelain}

Picture courtesy Bob Berry

2 1/4" X 2 3/4" (57mm X 70mm)

(Crown inkstamp)

 {Maker unknown}

Picture courtesy Bill Ostrander

2 1/4" X 2 3/4" (57mm X 71mm)

(Crown inkstamp)

 {Maker unknown}

Picture courtesy Bob Berry