THE INFLUENCE OF GEOLOGY ON HOKTTCULTURE. 405 



£5 the acre ; it is also a good building stone, as seen at Rochester Castle 

 and many bridges in the district. It is a calcareous sandstone, and 

 when burnt produces a very superior lime. The Hythe beds, of which 

 the Kentish Rag is a member, underlie Ightham, Mailing, Mereworth, 

 Wateringbury, Farleigh (which gives its name to the famous damson), 

 Banning, Allington, and Boughton, parishes producing much first-class 

 top and bottom fruit. 



The Upper Cretaceous series includes the Gault, the Upper Green - 

 sand, the Chalk marl, and the Upper and Lower Chalk. 



The Gault Clay divides the lower from the upper greensand. This 

 clay is solid and impervious, and generally blue in colour. Bricks are 

 made from it at Aylesford, Burham, Wye, Dunton Green, and Otford, in 

 Kent. In some places it is marly, and in consequence much more fertile ; 

 it is chiefly pasture. Fine oaks are seen on this soil in Surrey, and good 

 ash and elm grow over it in Oxfordshire. The Vale of the White Horse, 

 in Berkshire, is an example of the best soil on this clay, and its worst 

 soils are in Cambridge and Huntingdon. 



The Upper Greensand is one of the most fertile of the light soils, 

 especially where mixed with chalk marls. The noted hop-lands of 

 Farnham, in Surrey, are a mixture of chalk, greensand, gault, London 

 clay, and gravelly alluvium ; in 1846 the hop-lands in this parish were 

 valued at a rent of £20 the acre per annum, and some hop-land was 

 sold at £500 the acre. Phosphatic nodules are found in the gault and 

 upper greensand ; they were formerly ground down for use as manure. 

 Hops are grown over very similar soil at Canterbury. In the neighbour- 

 hood of Wantage (Berks) there are a number of orchards on this forma- 

 tion varying from half an acre to three or four acres in extent ; the soil 

 is some of the best in Berkshire. There are old orchards of large extent 

 at East Hagbourne. At Blewberry, at the meeting of the upper greens 

 and the chalk, cherries are extensively grown and the trees attain a large 

 size. At Mentmore (Bucks), situated on the upper greensand, fruit is 

 well grown on Lord Rosebery's estate. At Bromham (Wilts), on the 

 greensand, fruit and vegetables are well grown, and all fruit appears to 

 thrive well here. The principal fruit-growing district of Cambridge- 

 shire lies five to fifteen miles north-west of the university town ; in the 

 neighbourhood of Histon, Rampton, Cottenham, and Willingham, on the 

 upper and lower greensand, apples, plums, and cherries grow well, also 

 heavy crops of bush fruit, particularly gooseberries. It will be seen 

 from the above that the greensand is favourable to fruit, and that the 

 application of lime or chalk benefits it much. 



The Chalk, with its characteristic rounded hills, underlies a large area 

 of the south-east of England, forming a broad band fifteen to twenty-five 

 miles wide from south Dorset to the north of Norfolk, branching from 

 Salisbury Plain to the North Downs in Kent and the South Downs in 

 Sussex, also smaller areas in Lincoln and Yorkshire. 



The Chalk Marl, the lowest bed, forms good soil, especially where 

 mixed with greensand. 



The Lower Chalk, without flints, lies to the north and west of the 

 upper chalk, is greyer in colour, produces better soils, and is more valuable 



