158 



T. E. LONES — GRAVELS, SANDS, CLAYS, 



other places, the beds of loam or brick-earth are largely used in 

 making bricks. In the Hemel Hempstead district, where Tertiary- 

 clays and sands are also worked for the same purpose, the loam is 

 of great thickness, of good colour, and fairly free from pebbles or 

 flints. The bricks manufactured , from this brick -earth are of 

 excellent quality, of uniform colour, and of regular shape. 



The loams are usually bright red, reddish-grey, reddish-brown, 

 or brown, the colours being often so distributed as to produce 

 a mottled appearance, but this mottling is usually not well 

 defined. Occasionally the variation of colour is accompanied by 

 a somewhat stratified appearance, as shown in Section 6, taken in 

 a brickyard at Champneys. 



Section 6. — At Champneys. 



A. Soil. 



B. Brown brick -earth. 



C. Brick-earth with many flints. 



D. Brick-earth, sho^ving a coarse stratification. 



ZI. E. Dark brown brick-earth. 



Generally speaking, the loams are unfossiliferous, but Sir John 

 Evans discovered an impression of a small leaf in loam at Woodlune 

 End, as stated in Whitakers ' Geology of London,' vol. i, p. 290. 



Much doubt exists as to the relative ages and the modes of 

 formation of the various deposits of loam. Some beds in the 

 southern part of the County are closely associated with the Glacial 

 Drift which will he described further on, and were perhaps deposited 

 at the same period as the Drift. 



Flint-Geavel and Sand. 



The next beds which will be described are those shown on the 

 map as flint-gravel and sand. They occur as isolated patches over 

 the higher parts of the undulating countiy previously described; 

 in many cases the beds are intimately associated with the beds of 

 loam occurring over the same high ground. Some of the beds are 

 similar to those described by Mr. Whitaker as plateau gravel. 



