XVI. 



The chalk extends all over the County, but is overlaid in some 

 parts by the glacial deposits, and towards the S. and E. by the upper 

 tertiary strata ; but in the N. and W. it lies immediately below the 

 subsoil, and disappears again below the fens, so that it forms a basin 

 by dipping W. and S., in which lie the upper deposits, till at Harwich 

 a well, which has been sunk to the chalk, passes through 1000 feet of 

 tertiaries before the chalk is reached. This sinking, so close to the 

 border of the County, will give a good idea of the thickness of superin- 

 cumbent deposits in the South of the County. 



The Lower Chalk crops up at West Kow Ferry, near Mildenhall, 

 and in a quarry at that place a good section is exposed, shewing a red 

 band of 3ft. 5in. in thickness, and other well marked chalky strata con- 

 taining fossils typical of this horizon Holaster sub-globosus, Holaster 

 trecensis, Belemnitella plena and various species of Brachiopoda ; layers 

 of flint are conspicuously absent, a characteristic feature of the lower 

 chalk series. 



The Upper Chalk crops up at Claydon and Bramford, near Ipswich, 

 and various exposures may be seen along the banks of the Gipping, 

 Little Ouse and Lark. In the neighbourhood of Bury St. Edmunds 

 are several chalk pits, from which I have obtained typical fossils, and 

 stratified layers of flints are seen in almost every section. The most 

 common fossils to be obtained from the chalk are various species of 

 Echinodermata, Belemnites, Terebratulae and other Brachiopoda, 

 Inocerami, Ostrese, Sponges, Corals, Fish remains, and of course the 

 microscopic Foraminifera, whose cases make up so much of the chalk 

 itself. 



Along the Eailway cutting, near Higham and Kennett, the outcrop 

 of chalk is seen to have been much disturbed, the beds being ground up 

 and shattered by glacial action for several feet in depth. From the 

 chalk is derived the best part of the drinking water for the County, 

 wells being sunk to various depths to obtain a good and permanent 

 supply. The chalk itself is worked and burned for lime, which is used 

 in various ways and as a dressing for the land. 



In the S. and S.W., the chalk is immediately overlaid by the Eocene 

 beds ; at Sudbury, by the Thanet sands, which beds are also to be seen 

 in the valleys of the Brett and Gipping. Above the Thanet sands are 



