TOPOGRAPHICAL REMARKS. XVll 



part of the district. A map of it in that condition will be 

 found in Dugdale's Imbanhing and Draining. The worst 

 condition seems to have been attained at about the year 

 1600. This unfortunate state of things was attempted to 

 be improved, with variable success, by extensive drainage 

 works, most of which are now considered to have been 

 devised on a wrong plan ; and, although parts of the district 

 were very much improved by them, it is only recently that 

 the natural drainage has been to any considerable extent 

 restored by the thorough clearing of the mouths of the 

 rivers. Thus in large tracts near to the coast the pumping 

 mills are dispensed with and the water escapes to the sea at 

 nearly all times. 



Small spots formed of mounds of Boulder Clay or Gravel, 

 and the true Isle of Ely, which consists of an outlier of 

 the Lower Green Sand, are slightly raised about the peaty 

 flats, and are scattered like islands (which formerly they 

 often were) over the Fens. 



Botanically speaking the Pens have undergone an equally 

 if not more destructive change than the Chalk district. 

 The employment of steam has made the removal of the 

 water so certain that nearly the whole level may be cited as 

 a pattern in farming. With the water many of the most 

 interesting and characteristic plants have disappeared, or 

 are become so exceedingly rare that the discovery of single 

 individuals of them is a subject for wonder and congratula- 

 tion. There is scarcely a spot remaining (I only know of 

 one, near Wicken) in which the ancient vegetation continues 

 undisturbed and the land is suificiently wet to allow of its 

 coming to perfection. Owing to the necessary existence of 

 numerous ditches, to divide the fields and collect the water, 



b3 



