Peacock : The Fenland Soils. 



2. — The spring's which supply this water are most powerful. 

 The driest summer does not affect the supply. 



3. — These wells are deep circular ponds in the peat as a rule. 

 If the water is only deep enough they are covered with nothing 

 but Chara hispida in large masses from being- too deep for other 

 vegetation. 



4. — The excess of carbonate of lime has aided in the gradual 

 destruction and removal of the peat which once occupied the site 

 of these wells. 



5. — The ordinary peat growth flora flourishes round the edge 

 of these wells, and molluscs and fish are found in them. 



The only fish 1 have personally observed were the Common 

 Trout and Three-spined Stickleback. The shells were the same 

 as in the southern Marl, but not as frequent as one would 

 naturally have expected from a casual glance at the Shell Marl 

 of Trundle Mere. When we reflect, however, that one season's 

 deposit, say from six inches of matted Chara hispida, would only 

 be a white stain or coat as of the thinnest paint, the relation of 

 the shells to the inclosing" marl is easily explained. Chara 

 foetida is found in the neighbourhood, but I could only detect 

 C. hispida at Aylesby in the 4 Blow Wells.' It is an annual, 

 thickly coated with carbonate of lime, and flowers and fruits 

 plentifully — if I may thus speak of a Cryptogam. Year by year 

 the carbonate of lime which results from the decay of this species 

 in the winter accumulates on the floor of the wells, and is 

 gradually built up into a solid mass of marl like that found in 

 the Whittlesey district.* 



The marl of the Great Fenland attains its fullest develop- 

 ment in Sedge Fen, near Cross Bank, in Huntingdonshire, to 

 the south of us. There it is of a white friable nature, but is 

 much decomposed by the operations of agriculture. The un- 

 weathered mass is jointed so as to form large lozenge-shaped 

 lumps, and the main joints are very regular. Its boundaries, 

 like those of the Fen beds generally, whether peat or silt, can 

 only be approximately determined, as the deposit dies out with 

 a ' feather edge.' We have only to suppose that strong springs 

 from the underlying Oolitic Limestone supplied the clear and 



"It is worth noting-, perhaps, that these 'Blow Wells' never entirely 

 freeze and coat with ice even in the most Arctic weather. In the summer 

 of 1895, as tne l ate J- Cordeaux and I examined one at Great Cotes, he 

 said : — ' They are never covered with ice — not even this spring-. I shot 

 a score of duck from this well this season when there was no other open 

 water except these Blow Wells in North Lincolnshire." It is strange under 

 the circumstances that no bones of the Anseres have been obtained from the 

 Shell Marl. They have been found in the peat. 



Naturalist, 



