110 J. T. ELSDEN POST-TEETIAET 



tion, -would have consisted of bare sheep-pastures and open fields, 

 without trees. Instead of this we find that about 40 per cent, of 

 the total acreage of Hertfordshire is given to corn crops, 12 per cent, 

 to gieen crops, 6 per cent, to rotation grasses, and 4 per cent, is bare 

 fallow. Out of a percentage of cultivated land of 84-5 the total 

 arable land is OTS and permanent pasture 23"0.* ISow, within our 

 limited area, differences in climate and contour are not of sufficient 

 importance to have any effect upon the proportion of pasture-land 

 to corn-land, which must therefore be owing to conditions of soil, 



Fig. 5. — Section through the West of Hertfordshire showing the hare 



Chalk Escarpment. 



TtU 6ABDESDBH* 



" "■ IFIKCBOS r ' ^ 



HIKTUOHT. I I 



X. Post-glacial. E. Mid-glacial. C. Chalk. P. Gault. Z. Oolites. 



The influence of the drift covering is well seen in the strip of 

 land from Royston through Baldock and Hitchin, where the chalk 

 comes to the surface. Of this part Mr. Evershed says : " The 

 strip of thin chalk-land, with its wide open fields, and its turnip- 

 and sheep-farming, is so suggestive of Cambridgeshire that the 

 boundary of the counties at Royston may well be passed without 

 being remarked. The natural division is in the hills near Ther- 

 field, when you plunge at once into Hertfordshire proper, with its 

 woods, small enclosures, and heavily timbered fences. "f Again, 

 in the south-west of the county, the boundary line of the London 

 Clay is everywhere defined by a verge of grass, which terminates 

 with the outcrop of the Chalk. It is the more marked because the 

 drift deposits covering the Chalk are gravelly loams unsuited to 

 pasture. I It is not always, however, that the drift furnishes a 

 fertile soil ; although it generally affords facilities for improvement 

 by admixture and draining. The richest tract in the county is said 

 to be the valley of the Lea from Hoddesdon to Cheshunt, and the 

 worst land is the district east and south-east of Stevenage and the 

 gravels around Hatfield, North Myms, and Northaw. But even 

 on the most sterile soil the hedges and timber are thrifty, owing to 

 a favourable subsoil. § The distribution of timber is also to some 

 extent dependent upon the nature of the drift, for where chalk is 

 near the surface beech woods prevail. In a zone south of this, oak 



* Topley, " Comparative Agriculture of England and Wales," ' Joum. Roy. 

 Agric. Soc.,' 1871, p. 270. 



t ' Journ. Roy. Agric. Soc.,' vol. xxv, p. 271. 



X lb., p 283. 



j Trimmer, "Agricultural Geology of England and "Wales," 'Journ. Roy. 

 Agric. Soc.,' vol. xii, p. 482; and Evershed, "Agriculture of Hertfordshire," 

 'Journ. Roy. Agric. Soc.,' vol. xxv, p. 271. 



