Chiseldon to OoUingboume. 



97 



j comes in due course. But in villages on the upper greensand the 

 | carelessness that is usually exhibited is most amazing. 



The sanitation of village schools, where the greater part of the 

 ■juvenile population of the village is centred for so many hours 

 j dining the day is a most important matter ; here, again, no cesspits 



I should be allowed but all refuse should be bestowed daily in the 

 | soil. Where this method is not adopted epidemics are likely to 



II occur. . 



Thus, narrow as is the outcrop of the upper greensand, yet, from 

 [I the number of villages situated upon it, it is a most important 

 j formation. Agriculturally also it is important as forming the best 

 I land. 



The Lower Chalk. 



This is the division of the chalk next above the upper greensand, 

 [I The base of the lower chalk is marly, and is known as the chalk 

 B marl. The chloritic marl referred to before is the base of the chalk 

 marl, and shows strong current action with consequent erosion, and 

 contains fossils derived from the upper beds of the upper greensand 

 — the Pecten asper zone. 



The chalk marl is a thick-bedded marly chalk, well shown at 

 Chiseldon Railway Station. A little farther south a change sets in 

 ; and we find some thinner, harder, gritty, siliceous beds. These 

 •: seem to point to the fact that the sea of the lower chalk was 

 still within the influence of a current bringing fine sand. The 

 depth of this sea has been estimated at from three hundred to four 

 hundred fathoms. The glauconite so abundant in the upper 

 greensand lessens in the chalk marl till it disappears in the upper 

 beds of the lower chalk. 



The lower chalk near the escarpment occupies a considerable area, 

 so that it is there an important division. 



The cuttings in this division, owing to its much greater thickness 

 — the dip not varying very much — extend for some three miles along 

 the line, a great contrast to the narrow outcrop of the gault and 

 the upper greensand. A reference to the diagram where this 

 division of the chalk is marked 4c Will show this fairly well. 



