280 



Farming of Lincolnshire. 



stratum of clay in the southern parts of South Holland (Gedney 

 Hill, &c.), and in Cambridgeshire (Wisbeach St. Mary's, &c.), 

 running in veins or ridges a few feet higher than the surround- 

 ing fen, and, at times, scarcely a quarter of a mile in width. In 

 some parts of the level, where this silt is absent, occurs a 

 stratum of peat from 1 to 3 feet thick, resting upon beds of 

 drift. In the VVitham fens, west of the river, this moor, one foot 

 in thickness, containing branches of trees, rests upon a bed of 

 sand 1 foot in thickness, beneath which is the Oxford clay ; and 

 near Bardney, where the same clay rises up from under the fen, 

 the peat stratum is near the top, and in it have been found 

 immense trees of oak and fir, their roots standing upon a thin 

 bed of sand, and striking downward into a bed of blue boulder 

 clay. The same peat is found about 2 feet below the surface of 

 the fens east of the Witham, probably dipping under Wildm.ore, 

 &c. fens. It has been found at Boston about 20 feet from the 

 surface, resting upon sand, gravel, or stony clay. The moor is 

 several feet lower than lovr- water mark, and therefore there must 

 have been a considerable change in the level of either land or sea 

 since it was formed. 



The next bed in the series is the soft blue clay, which is found 

 almost everywhere under the peat fens, and seems to be the 

 muddy sediment left by stagnant lakes and sluggish rivers. 

 This clay, varying sometimes to a red clay (as in some parts of 

 Deeping Fen), or a whitish silty clay (as in the Witham fens), 

 extends throughout the greater part of the level, and must have 

 been subject to the overflowings of the tides, for channels of 

 creeks with banks of raw silt exactly like our present salt-water 

 marsh creeks are found intersecting it ; and in almost every part 

 of the fens veins of silt (apparently the warped -up courses of 

 creeks) may be traced within it in nearly every direction. Sea- 

 shells are not abundant in the clay, but lie plentifully in the silt 

 veins and on the surface of the clay. From the fluviatile and 

 fresh water shells which are contained in it, and in the peat 

 which overlies it, the water from which it was deposited appears 

 to have been partly salt and partly fresh: indeed from the nu- 

 merous old river channels, shallow and circuitous, which have 

 been choked up and dried within the historic period, it is easy 

 to form an idea of the number of wandering courses the fen 

 rivers must have formed for themselves, when pouring down in 

 swollen volume from the hills into a wide horizontal plain, where 

 every direction offered equal facilities or hindrances to discharge. 

 These channels, by diffusing the waters, lessened their force and 

 momentum seaward, and consequently the slightest impediment 

 or tidal bar could stop the stream, change the current, and pro- 

 duce an inundation. Each bend in the tortuous channels re- 



