Peacock : The Fenland Soils. 



181 



Willow, Reed, and the whole family of fen plants from the White 

 Water Lily to the smaller species of Chara. From the upper bed 

 only: — The Elm (Ulmus montana), Ash, and Holly. From the 

 lowest level of the lower bed the Dwarf Birch only, for the 

 Arctic Willow {Salix polar is) has not yet been discovered in 

 Lincolnshire. Thus the great Fenland supplies us with the 

 fullest and most valuable evidence as to the antiquity of our 

 forest trees ; nay more, that they loved the same class of soils 

 then that they prefer to-day. For instance, the Yew and Holly 

 are generally found on gravelly soils. The insects, fish, birds, 

 and mammals of the peat prove in other ways exactly what 

 might be expected under the circumstances of the case, but 

 I cannot give you instances to-night. 

 t As the under peat comes to the surface as a fringe along the 

 Witham and to the W. and S. of the Fenland it is very difficult 

 to keep the beds quite distinct, but where the silt lies between 

 them there is no difficulty. The upper or modern bed and the 

 lower where there is no silt contain late flint implements and 

 signs of Roman occupation, and may date back for 100 to 

 2,500 years, as the case may be, but can hardly be earlier, from 

 the rate at which the silt has been deposited, and the position in 

 which the beds are found in respect to it. The lower peat must 

 have ceased growing at the time the brackish water of the 

 Wash began to deposit the silt, so we can easily assign an 

 approximate date to the period at which the lower peat bed 

 ceased to be formed. Some idea of the rate at which the silt 

 deposits have taken place above it may be gathered, as my 

 friend Mr. Wheeler has pointed out, from what is now going on 

 and from the area of the land which has been recovered from 

 the sea during the last sixteen centuries, for there is no reason 

 to suppose the rate has ever fluctuated much either way. The 

 greatest accretion of land from silting up has taken place at 

 the head of the old Roman bay at Briker Haven, in South 

 Lincolnshire. Here successive enclosures have taken place from 

 time to time, until the bank made by the Romans at Holbeach, 

 for the protection of their corn land from the sea, is left from 

 three to four miles inland. Now granting, which cannot be 

 disputed, that these banks were made from 1,500 to 1,600 years 

 ago, and setting the present rate of growth at from about 

 9 feet to 10 feet a year; allowing the same rate of accretion 

 in past ages as we find at present, it would take 13,000 to 

 15,000 years for the formation of the alluvial deposits pi the 

 present Fenland above the lower peat stratum. When trees are 



1902 June 1. 



