4 1/8" X 5 1/8" (104mm X 130mm)

No markings

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Picture courtesy Bob Berry

4 1/8" X 5 1/4" (104mm X 133mm)

(top incuse) Melbourne

{Maker unknown}

Picture courtesy Bob Berry

4" X 5 1/4" (101mm X 133mm)

(top ink stamp) FB / 35

{Fire Brick}

Picture courtesy Bob Berry

4 1/4" X 5 1/4" (107mm X 133mm)

(top ink stamp) R.F. LTD / 34

{R. Fowler Ltd.}

Picture courtesy Bob Berry

4" X 5 3/8" (102mm X 137mm)

(top incuse) PERMASITE

                 LEADLESS

               GLAZE

Picture courtesy Teresa Dempsey

4" X 4 3/4" (102mm X 119mm)

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No markings

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Picture courtesy Teresa Dempsey

4" X 4 7/8" (98mm X 123mm)

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No markings

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Picture courtesy Bob Scafe