ON THK LEA VALLEY. 5 



section. Elsewhere the proportions of the two would vary 

 extremely in the course of 20 yards or less, as in Fig. 2. Some- 

 times the loam towards its base became very dark and peat-like 

 in appearance, and its line of junction with the underlying gravel 

 very irregular, as in Fig. 3. Occasionally, between the gravel 

 and the surface loam, a thin irregular bed of shellmarl appeared, 

 or a definite bed of peat, formed of the remains of water or 

 marsh plants, as in Fig. 4. Again, at about the level of a bed 

 of peat of the kind just mentioned, formed of the remains of 

 plants which had grown and decayed where ihe peat is now seen, 

 tree and plant remains which had been deposited under totally 

 different circumstances were occasionally visible in irregular 

 bands towards the top of the gravel, as in Fig. 5. 



The shell marl was usually in thin, irregular, lenticular 

 bands, seldom exceeding ift. 6in. anywhere in thickness, and 



Fig. 2. New Reservoirs, Walthamstow. Height of Section about 9 ft., 

 length about 50 yds. 



disappearing in the course of 20 or 30 yards, as in Fig. 4. But 

 at one spot near the outfall of the Ching the section consisted of 



ft. in. 

 Soil .. .. .. .. ..16 



Sand and loam with many shells . . . . 46 



Gravel 

 The shells were those usually making up the shell marl. 



At another spot the beiis were — 



ft. in. 

 Clayey loam, a little shell marl towards the bottom 3 o 

 Gravel 



At a third place was seen — 



ft. in. 

 Soil and clay . . . . . • ..40 



Shell marl . . . . . . ..13 



Peat . . . . . . . • . . 16 



Gravel 



In this case the shell marl retained the above thickness for 

 a horizontal space of about 3ft., the whole band disappearing in 

 less than twenty yards. 



