The top is of a type popular in the 19th Century and was cut from a septarian nodule. Such nodules are formed when a mixture of clay, iron and calcium carbonate is concentrated as a jelly within a clay bed. As this jelly solidifies and dries, it cracks internally, forming fissures which gradually fill with calcite. These calcite deposits create the strong divisions which characterise the nodule when cut. Nodules are often found in London Clays and vary tremendously in size.
We are grateful to Henry Buckley, Esq. of The Natural History Museum, London for his help in preparing this catalogue entry.

A similar centre table with ebony veneer and inset septarian nodule top, was offered anonymously, Christie's South Kensington, 12 October 1994, lot 438.