270 A Geological Sketch of the Valley of the Kennel. 



are all of marine forms ; and during its deposition the land seems 

 to have gone on subsiding and the sea encroaching ; for the ocean- 

 bed, which immediately overlies it, has a much more extensive area 

 stretching east and west from Berkshire to Suffolk and covering a 

 large portion of Essex, Middlesex and Kent. The neighbourhood 

 of Hungerford probably formed the western shore of that ancient 

 sea, and the mass of black flint pebbles, which lie eight or ten feet 

 in depth, about a mile south of Kintbury, occupy perhaps a portion 

 of the coast line on which the surging waves were wont to beat. 

 Then began the deposition of strata known to geologists as the 

 " Woolwich and Reading series." Most of the bricks and tiles in the 

 district of Newbury and Hungerford are made of clay and sand 

 belonging to this formation. Between those towns it crops out 

 abundantly along the hill slopes of the Kennet Valley, underlying 

 the gravel on the north side between Speen and Wickham, and on 

 the south from the river to the base of the chalk hills, where a 

 narrow zone of it is exposed. At its junction with the chalk in 

 many of the claypits, as at Speen and Shaw, e.g. a bed of oyster 

 shells is found, very like, though distinct from existing species ; 

 and they are invariably perforated with small holes, the work 

 no doubt of parasites, similar to those which drill our modern 

 oyster shells. The mineral character of this formation is some- 

 what variable. Its lowest bed generally consists of sand and 

 pebbles ; and the remainder of clays, mottled red, blue, and 

 brown, intercalated with layers of sand. Fossils are abundant 

 in those beds at Woolwich and elsewhere ; but in the district 

 under notice very few exist besides the oyster shells above men- 

 tioned ; and those which occur are in a very perished condition. 

 They consist of sharks' teeth, bones of turtles, and a few small 

 shells of marine origin.' At Woolwich the formation yields 

 I'resh-water fossils in abundance ; and vegetable remains are also 

 common. At Reading, too, Mr. Prestwich discovered in the 



1 The following have been found in the bottom-bed of this series at Shaw 

 clay -pit: — CAe/onj'a, bones of. Zamwa, teeth of. Ostrea Bellovacina. Car- 

 dium. Tellina. Cythera Mulleri, Echinoderm, minute species of. Glohulina, 

 Memoirs of the Geological Survey, No. 12, p. 21. 



