276 



Farming of Lincolnshire. » 



with rounded and white flints ; and there is another deposit at 

 Partney. These p:ravels and sands may, however, be outliers of 

 the plastic clay. The most extensive tract of drift is that which 

 extends itself from the Ancholme flat to the fens at Tattershall, 

 a length of 25 miles ; and from the green sand district to the 

 Witham fens, a breadth of 10 or 1 1 miles. The Oxford or 

 Kimmeridge clay is here covered in nearly every part by a great 

 thickness of transported earths, forming three different kinds of 

 soil. The northern and western portions of the district about 

 Wragby, &c.^ have generally a surface of clay, not very strong, 

 but producing corn of good quality, — resting on a subsoil of 

 mixed clay and sand, or gravel, or, where that is not the case, 

 white marly clay. Approaching the Wolds, the white clay (or 

 chalk breccia) is at the surface, resting at a considerable depth 

 upon the Oxford clay, and at its eastern edge capping the 

 hills of green sand — that formation occupying the valleys as a 

 red or brown sandy clay containing flints. It is a white greasy 

 marl, containing flint stones, large blocks of chalk and flint, and 

 rounded pebbles of chalk in great numbers. It is generally 

 absent from the valleys, but attains to a considerable thickness 

 on the hill summits. Marden Hill and Hundleby Wood, to the 

 west of Spilsby, are two green-sand hills capped by deep de- 

 posits of this chalk drift; they are about miles apart, and 

 some distance from any larger bed of the clay. At Hareby, 

 where it hides both sandstone and blue clay, it is found of 

 various depths, from a thin coating of a few inches to a deposit 

 of more than 14 yards in thickness. This clay forms a most 

 valuable material for applying to the sand land, and is also burnt 

 for lime. Like the chalk, it effervesces with acids, and yields a 

 large percentage of weak lime, the marl burning into powder. 

 The soil upon this kind of drift is wet and sticky, and much of 

 it is very poor in quality. The southern part of the drift district 

 has generally a sandy soil resting upon gravel. The Tower 

 Moor, east of the Witham fens, has been partially and with dif- 

 ficulty reclaimed from natural sterility, many parts of it pro- 

 ducing nothing but stunted furze and ling. The gravel is there 

 about 12 feet deep, upon the Oxford clay. At Tattershall, 

 upon the sloping grounds that rise up from the fen, 4 or 5 feet 

 of fine gravel conceal the same clay. From Tattershall through 

 Coningsby, Tumby, Mareham, Revesby, &c., the same sandy 

 gravel forms the surface, except in those places where the clay 

 is left bare. In these and neighbouring parishes there is every- 

 where plenty of water, which breaks out of the hills in springs, 

 and these, if not cut off, find their way into the fens below. The 

 hill behind Revesby Abbey, rising gradually to an elevation of 

 140 feet above the fen^ consists of coarse Norfolk marl," from 



