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ENGLISH AGRICULTURE. 75 



the upper oolite, a point which ought to be remembered, and 

 which will be brought out as important presently. 



Next, turning to the middle oolite, we shall find that it 

 is ushered in with certain thin limestone rocks, which are 

 known as the upper calcareous grit, followed by the coralline 

 oolite, followed again by the lower calcareous grit, and again 

 y the Oxford clay and Kelloway rock. Those are the main 

 ocks which compose the middle oolite ; but, like the last 

 formation, the calcareous grits and coralline oolite are rather 

 exceptional than general, and the Oxford clay occupies 

 a large proportion of the area occupied by the middle 

 oolite. So much is this the case with reference to both the 

 upper and the middle oolite, that frequently the Kim- 

 meridge and the Oxford clays alone represent these two 

 brmations, passing together in a southerly and south-westerly 

 irection, and giving a tract of clay soil upon the north and 

 west of the greensand formation. And as the greensand is 

 itself only narrow, this compact bed of clay seems to pass 

 with little interruption from the north-west flanks of the 

 chalk formation. This is highly interestingly shown in the 

 unty of Lincolnshire, a county in which the geology of the 

 istrict corresponds in a striking manner with its agriculture, 

 t me briefly recall the distribution of the soils in Lincoln- 

 hire in this connection. Upon the extreme east is a district 

 f marsh, then westward of the marsh are seen the chalk 

 'olds passing southwards to Burgh. Westward of the chalk 

 a district which is known as the clays, the district which 

 now occupying our attention ; the clays lie upon the 

 est side of the chalk, so that in Lincolnshire we have suc- 

 ssively from east to west marsh grounds, chalk hills, clays, 

 d finally, although this is anticipating, the Lincoln heath; 

 hose four marsh, wold, clays, and heath passing from 

 north to south of the county, and dividing it into four well- 

 defined strips. 





