284 



Farming of Lincolnshire. 



loaded with mud, sand, and animal and vegetable substances, 

 flowed for a considerable distance inland. The salt water, by its 

 greater specific gravity, would, as' it were, undermine the freshes, 

 the weight of which would fix a limit to the advances of the sea ; 

 and where this hindrance occurred (varying in locality according 

 to the periodic height of the tide and volume of fresh water from the 

 uplands), a deposit of slime would take place. Every bar of this 

 kind raised would act as a check to the tidal waters, and thus pre- 

 cipitate fresh matter near it, and on that side (next the sea) from 

 whence the sediment came. It is in this way that the sea has 

 formed upon these flat shores, liable to freshwater inundations, a 

 deposit which is lower and thinner as it recedes from the sea, 

 and thus that it has covered so large a portion of the peat above- 

 mentioned with alluvium. The first bed upon the peat is from 4 

 to 16 or more feet in thickness near the coast, and thins off" like a 

 wedge as it proceeds inland until it altogether vanishes, and the 

 peat comes to the surface. It is generally a mass of silty clay, 

 without marks of lamination, traversed by innumerable small rusty 

 veins, apparently of decayed vegetation and red sand. The Roman 

 banks were founded upon this stratum, but since they were made 

 the sea has deposited several feet of soil outside the banks, and 

 also for 1 or 2 miles inland, covering the clay. This bed forms 

 the clay of Marshland in Norfolk, and of the central parts of 

 South Holland (called " the Fen Ends "). It is sometimes a hard 

 gaulty clay, with red and blue streaks, or a hard blue clay, very 

 stiff and difficult to manage ; but it generally contains beds of silt, 

 either under, above, or w^ithin it — like sandbeds in the new w\arp 

 land. It often rests upon the buttery blue clay, and, approaching 

 the black land, becomes of a peaty nature. Northward of Spalding 

 it extends to Donington and Swineshead, &c., lying between the 

 fens and the newer marsh land near the coast. In Heckington 

 and several other fens it is found as an alluvial clay and silt, and 

 in Holland Fen and Wildmore Fen it is a deep loamy clay, and 

 sandy loam upon a subsoil of clay or silt. In the rich grazing 

 district of Boston, Kirton, Wigtoft, Fosdike, &c., and the breadth 

 of good land upon which the principal South Holland tow^ns are 

 built, the soil is a remarkably rich brown loam, from a few inches 

 to 4 or 5 feet in depth, resting upon silt ; and the higher grounds 

 appear to have intercepted and retained a large proportion of the 

 vegetable matter floating in the waters after the principal deposit 

 had taken place. North-eastof Boston it is of the same character, 

 the portions adjoining the fen being a stiff blue clay, having 

 higher spots of silty soil about its surface. Along the North 

 Marshes it is a rich clayey loam, varying to a friable sandy loam 

 or a tenacious marine clay, but generally fertile. It rests upon 

 the peat stratum, and along many parts of this coast is 20 feet 



