REACHES, ETC., OE THE SOUTH OF ENGLAND. 321 



referred to this drift, and not to a high-valley or fluviatile drift with 

 which, though with a feeling of douht, I associated it, as I then saw 

 no other alternative. 



The large erratic blocks of Tertiary sandstone, several of which 

 have been recorded by Col. Mcols,^ occasionally met with at different 

 levels up to 200 feet or more, may possibly be of this age. There 

 are no foreign boulders amongst them, — all are derived from adjacent 

 Tertiary strata. 



(19) The Chalk District of Kent and Sussex. — In my paper on 

 the formation of the Darent Valley ^ I briefly alluded to a red loam 

 or clay lying on the slopes of the Chalk hiUs, and overlying the 

 white Chalk Rubble so common in that district. This red loam is, 

 like the Chalk Eubble, rarely more than a few feet thick, and con- 

 tains chalk-flints but little worn. It reposes upon a very uneven 

 surface of the Chalk Eubble, the line of division between the two 

 being sharp and distinct. 



^. ^ „ ^ . ^ ^ In freshly ploughed fields this 



Pig. W.-Secuon on SepTiam ^^j^^ ^^ ^^^^ ^ j ^^ it 



Harm, near SUreham. ^^^^^ ^^^ slopes - sometimes 



forming a fringe extending for a 



^^^ short distance from the brow of 



^^■^^ >Ty, X ^y^^-^]^' scendingthe whole length of the 



"^ '' ' ' ^'^^yjf^^^^^j ^t^' ^ slope down to the valley below. 



In the first case it forms a belt 



"• p^rfer^LTmr ™d' trtiaiy f -^ ^ "f."' T''''^ ^™'?!- ^ 

 pebbles. tones on on the lower part oi tne 



2^ Chalk-rubble of broken chalk and slopes to quite white. It is clear, 



sharp angular flint-fragments in a from this fact of its becoming 



chalk-paste passing into- ^^^^^^^ ^^^ ^f^^j^ ^^11 disap- 



2. Solid Chalk, with layers of flmt. . ., , i ^i i 



•^ pearmg as it descends the slopes, 



that it has its origin from matter above and higher up the hills. It 

 is, in fact, closely associated with the Eed Clay-with-flints, which 

 so constantly caps the higher Chalk hills, for it is only in the 

 valleys intersecting these hills that this red and white colouring of 

 the slopes is to be seen. It is due to a slight wash from the hill- 

 tops of the plateau-drift ; but, though it consists of a basis of this 

 clay, it is more or less mixed with sands from the associated Tertiary 

 outliers, and with flints fresh from the Chalk. 



It is impossible to ascribe this red ground either to surface- 

 decomposition — for, in that case, it should extend over all the bare 

 Chalk slopes — or to rainwash, for then it should have formed rills 

 scoring the hillsides and leaving cones of debris at their base, 

 whereas the spread of it has all the uniformity and regularity of an 

 even tint of colour. I can only ascribe it to the one general cause 

 to which I would assign the origin of the Head and the other con- 

 temporary drifts. 



\ Geol. Mag. for 1866, p. 296. 



* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 155. 



