Stone in Archaeology Database

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Lower Greensand Group, Hythe Formation.

Two layers are important: the Ragstone which is a bluish/grey colour and the Hassock which is a grey colour.

The ragstone is a hard, coarse grained, sandy limestone comprising rounded, detrital grains of quartz and glauconite, cemented by calcite (85% of the rock is calcium carbonate). It occurs in layers from 10 - 90 cm thick. This is interbedded with layers of hassock, a loamy, calcareous, glauconitic sand (Worssam & Tatton-Brown 1993: 93-4).

The proportion of the minerals may differ considerably and the lithology varies considerably along its outcrop. There is every gradation from a sandstone with abundant calcerous cement (mainly of organic origin) to a shelly limestone with scattered sand grains. A predominance of silica indicates a sandstone and in fact the amount of silica of some beds rises to the level where these beds are indeed regarded as sandstones and not limestones.

This stone can be mistaken for Reigate stone, however Kentish Rag is not micaceous and is particularly calcareous with rounded rather than amorphous grains of quartz.