72 THE PRINCIPLES OF 



the chalk counties successively we shall find that each county 

 has its Down breed of sheep, some being more conspicuously 

 known than others. I may mention Oxford Down sheep 

 (a crossed race), Wiltshire Down sheep, sheep of the North 

 Downs or Kentish Down sheep, sheep of the South Downs 

 or Sussex Downs, sheep of the Hampshire Downs, and 

 sheep belonging to the Dorset chalk district, known as the 

 Dorset horned sheep. All of these sheep, with the exception 

 of the last-named, may be described as brown or black-faced 

 and shanked, with somewhat close or short wool, thriving 

 well upon a dry upland, and preferring a short and wiry dry 

 pasture to a profusion of long and coarse grass, such as is 

 found in lower grounds or valleys. Another peculiarity of 

 the soils of the upper chalk is that the hills are very fre- 

 quently capped with a better class of land than the slopes 

 and subsidiary valleys. This is well known to land valuers, 

 and appears to be caused by the admixture of the soils of the 

 upper chalk with the soils of the London clay, the most of 

 which have been removed by denudation, but which still to 

 some extent cap the rounded summits of the hills of the 

 upper chalk. The tops of the hills of the chalk are accordingly 

 often of stronger and better character than their flats and slopes. 

 Having sketched out the general pathway of the chalk, 

 the next formation which must occupy our attention is the 

 greensand. The greensand may be spoken of as forming 

 a ribbon or closely applied band upon the north and west 

 boundary of the chalk formation, bearing out the rule which 

 we have found to hold good in the distribution of our soils. 

 This sinuous ribbon of green, shown on the geological map, 

 which is known as the greensand, will be found to be properly 

 divided into the upper greensand and the lower greensand, 

 the two being divided from each other by the gault clay. 

 Glancing at this formation, we find that the upper greensand 

 is as a rule a fertile soil, while the lower greensand is barren. 



