and Marlborough Railways. 



179 



the deposit called Clay- with -flints by the Geological Surveyors, 

 and is covered in places by clayey sand or Brick-earth. The latter 

 is sometimes so like the mottled clays and sands of the Woolwich and 

 Reading series, that it is only after repeatedly finding angular chalk 

 flints in it, or unmistakeable drift beds under it, that I have come 

 to the conclusion that the Tertiaries do not occur in situ. An 

 exception may perhaps occur at the first bridge over the Railway, 

 where there is a bed of fine clean sand covered by mottled clay. 



The sections in these cuttings were obscure, from the fact of their 

 not being deep enough. The Chalk was only here and there touched 

 upon, and the relation of the overlying deposits was only made out 

 by the light thrown upon them in the cutting near Warnhams. 

 This, throughout its length, exhibits a good section of the Chalk, 

 Clay-with-flints, and Brick-earth. 



Figs. 6 and 7, 

 were drawn while 

 the cutting was 

 in progress, but 

 other and similar 

 sections are still 

 visible. The up- 

 per surface of the 

 Chalk is extreme- 

 ly irregular, jutting up in peaks 

 of all shapes, between masses of 

 Clay- with-flints. It is covered 

 with about an inch of black 

 clay, and the flints at the 

 bottom of the Clay-with-flints 

 are often black coated. The 

 .Bandof flint. Clay-with-flints is here about 6 

 feet thick, and its upper bound- 

 ary repeats the general outline 

 of the top of the Chalk, how- 

 j. - ever irregular that may be. It 



consists of clay more or less sandy, containing flints of all sizes quite 



o2 



Chalk. 



Fig. 6. « A Sarsen-stone embedded in the brick-earth 



Brick- 

 earth. 



Clay-with 

 flints. 



