406 MarJcet-GnnJen Soils and Crop ft 



laid down by a much larger river which probably flowed through 

 greensand country from Flitwick to Shctt'ord. The characteristic colour 

 of these deposits, especially the extensive area from Broom to Stanford, 

 is brown, hence the name "old brown" was applied to it to distinguish 

 it from the more recent dark soil formation at a lower level. 



It was found tiuit tiio remaining gravel soils of the district, witii the 

 exception of a small area, which will be described later, could be referred 

 to either one or the other of these two soil formations. It was found, 

 however, convenient when giving the analyses of the gravel soils in the 

 Appendix to group the samples together according to the localities from 

 which the}- were taken. Thus any small variation due to local causes 

 woidd be revealed. The area which has been referred to as an exception 

 will be discussed later under the heading "Heavy brown soil formation." 



The old brown soil formation is of such great extent and its areas are 

 so widely separated that it is only to be expected that local causes will 

 produce some slight variations in texture in different localities. There 

 is, however, such a great resemblance in general characteristics that 

 all the areas have been included as one soil formation. In order, 

 however, to describe fully its properties and the effect of local conditions 

 it has been subdivided into the following areas: 



(1) Biggleswade Plateau. 



(2) Stanford-Broom Plateau. 



(3) Biggleswade Common Plain. 



(4) Ouse Brown Gravels. 



The Biggleswade plateau on the east side of the London Road 

 resembles the Stanford-Broom plateau very closely in mineral structure 

 and texture, but it has been greatly improved by heavy manuring with 

 London dung. There is easy access to the Biggleswade railway station 

 and evidently it has been under market-garden culture for a considerable 

 number of years. The organic matter has been very notably increased 

 by this heavy manuring and this makes it far more suitable for the growth 

 of such crops as carrots and parsnips than it otherwise would be. 



The Stanford-Broom plateau has been taken up by market-gardeners 

 only in comparatively recent years and, owing to the distance from any 

 railway station, the quantity of dung applied is very much less than in 

 the previous case. It also has the disadvantage of a slightly increased 

 percentage of stones and fine gravel, in one sample these fractions being 

 10 per cent, higher than the average for the Biggleswade soils. Owing 

 to the small percentage of organic matter the soil on the Stanford- 



