98 



Geology of the Keytliorpe Estate. 



respecting tlie geological position of which little is known, is 

 situated in the marlstone division of the lias. This point should 

 be determined by a careful examination of the strata in which it 

 occurs, at the localities where it is worked, and by tracing their 

 outcrop through the intermediate space. 



The estate contains soils all ranking as clay, but of very 

 different values ; the value, in their natural state, varying from 

 less than 20^. to more than 505. Under the ordinary system of 

 Leicestershire management, they are devoted almost exclusively 

 to permanent pasture and summer grazing. By draining and 

 subsoiling, or double ploughing, portions have been converted 

 into arable land, which yields splendid crops of swedes, ^vurzel, 

 and clover, thus furnishing a valuable auxiliary to the grass-land 

 for the winter feeding of stock. 



By the system of draining pursued, the worst soils of this 

 estate, whether converted to arable or retained as pasture, have 

 been doubled in value. 



The natural variations of these soils do not arise from varia- 

 tions in the mineral characters of the substrata of lias, but from 

 variations in the distribution of the superficial deposits. These 

 consist of the three varieties which I have enumerated — namely, 

 boulder clay, or lower erratic tertiaries ; gravel and sand of the 

 upper erratics ; and warp-drift. The lower erratics present their 

 usual form of boulder-clay or till, and contain large chalk flints, 

 subangular fragments of chalk, and other detritus extraneous to 

 the lias ; the upper erratics consist of gravel containing chalk 

 flints, and so much limestone that the larger fragments are col- 

 lected for lime-burning : both deposits have been much denuded. 

 From the rarity of sections, and from the covering of warp-drift, 

 the boulder-clay is not often exposed ; but some holes, which 

 Lord Berners caused to be opened for my inspection, clearly 

 established its presence, and showed that the rolled gravel rests 

 upon it. I observed similar boulder-clay, several years ago, on 

 the summit of the oolitic ridge near Desborough. 



The gravel covers many of the tabular hills of lias at Key- 

 thorpe, to the depth of 12 and 15 feet. 



The variations of soil follow the analogies which I have 

 observed in other districts. The poorest soils are upon the steep 

 sides of the hills where there is little or no covering of warp- 

 drift on the lias clay. There are better soils on the summits of 

 the hills, consisting of a warp-drift of clay or clay-loam resting 

 on the rolled gravel. These soils are valued at 30^. the acre. 

 The best soils of all are in the bottoms of the valleys, or on the 

 long slopes where there is a deep covering of warp-drift. These 

 are valued at from 405. to 6O5. 



The estate constitutes an upland district near the head waters 



