22 
ON THE UNDERGROUND WATERS OF LINCOLNSHIRE. 
BY C. E. DE RANCE, ASSOC. INST. C.E., F.G.S., F.R.G.S., F.R. MET. SOC, 
Secretary of the Underground Water Committee of the British 
Association. 
The County of Lincoln occupies an area of no less than 
1,775,000 acres, or rather more than a million and three-quarters, 
and, with the exception of Yorkshire, is the largest county in 
England. It is drained entirely by streams flowing into the 
German Ocean, of which the "Welland, the "Witham, and the 
Ancholm are the most important ; to the north-west a small 
tract drains into the Trent ; and to the north-east small streams 
flow off the Wolds direct into the sea, or the north of the Humber. 
The surface geological structure is largely modified by thick 
deposits of Glacial Boulder Clay, while below the strata range from 
the Keuper Marls, under the Trent on the west, to the Upper 
Cretaceous on the eastern margin, where they disappear below the 
overlying glacial drift, about 600,000 acres consist of porous rocks, 
but these are in part covered by impermeable Boulder Clay. The 
"Witham drains no less than 176,000 acres of fen-land, the Welland 
77,000 acres. 
More than 80 per cent, of the land is cultivated ; 35 per cent, 
of the whole area, or nearly half the cultivated area, grows corn crops, 
half the latter being wheat. Green crops occupy 12\ per cent, of 
the total area, and fallow and grasses and clover under rotation 
nearly 9 per cent. Permanent pasture is nearly 26 per cent., and 
towns, woods, gardens, and waste 19 per cent. 
All water, whether visible in streams and rivers, or concealed 
beneath the earth's surface, being derived from rainfall. In Appendix I. 
I have tabulated the rainfall at four local stations from the returns 
furnished to Mr. Symons, F.R.S., and published by him in his annual 
volumes of "British Rainfall." In 26 years, at Lincoln, the rainfall 
has been 20 inches or less, no less than 9 times, and on 2 of these 
