# Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/208

Immediately incumbent on the chalk is a stratum 2 feet thick of green sand containing numerous oyster shells. Many of these are entire, having both their valves united; but the animal matter being entirely gone, and the shell not having undergone the process of petrifaction, they are white and extremely brittle, and separate into laminæ. Fishes teeth are also found with them. Over this is a bed 8 feet thick of a bluish rough clay, then fuller's earth 2${\displaystyle \scriptstyle {\frac {1}{2}}}$ feet, and line white sand 7 feet. Next is a stiff red clay, probably the plastic clay, of which tiles are made. This is much thicker than any of the other beds; and over is the alluvial soil. These strata are known to extend for several miles with little wariation.