On the Application of Geology to Agriculture. 



273 



whatever the local circumstances (so long as not too steep to be 

 ploughed), invariably produced good wheat, it was a triumph 

 for agricultural geology to discover that these fields were invari- 

 ably upon the Oxford clay^ or rather where the lower beds of 

 the calc. grit become mixed up with that formation ; and^, com- 

 paring the comparative value and growth of timber produced 

 upon different portions of the slopes where too steep for plough- 

 ing^ it was satisfactorily established^ that oaks flourished the best 

 upon this identical stratum or zone wherever existing. It also 

 appeared on examination that the lowest bed of this same Oxford 

 clay was the only water-tight stratified bed on the estate^ and threw 

 out every spring on the hill sides — a fact which^, had it been knov/n 

 some years ago^ coupled with the knowledge we now possess of 

 the thickness of the superincumbent strata, would have Scived 

 much money, expended in sinking for wells upon the highest 

 range of these hills. The facility Avith which w^ater had been 

 obtained by shallow wells on a neighbouring summit had pro- 

 bably misled the then managers of the estate. Dr. Smith disco- 

 vered that the height last named was covered^ with diluvium, 

 which had a water-tight seam in it below the gravel, a few feet 

 below the surface, and thus produced the well or spring. In this 

 case, geological knowledge would have shown at once the different 

 construction of the two hills. It is a curious fact that the greatest 

 mass of diluvial matter upon the estate should be on one of the 

 highest summit levels ; thus giving water at an easy depth, and 

 forming a tract of good grass land. 



I may therefore fairly say, that the geological map and survey 

 of my estate (which I allow is peculiarly adapted for such an ex- 

 periment, through the variety and number of the subdivisions of 

 the oolitic series which develop themselves successively upon the 

 surface,) has not only explained the reason of the discrepancy be- 

 tween the soil and productiveness of neighbouring fields — a matter 

 of great interest, and tending to develop the true conditions of 

 vegetable life — but that the following positive practical results will 

 also have been derived from it : — 



1st. The knowledge of applying lime to advantage over the 

 property. 



2nd. Laying down fields to advantage to grass, and where and 

 how to plant wheat. 



3rd. What sorts of trees to plant upon each stratum. It is 

 moreover important to possess a sort of theory of the whole series 

 of soils, which explains many of their peculiarities, and furnishes 

 hints for future agricultural operations. 



I have before observed, that the best grass land upon the hills 

 is upon the coralline oolite beds. The analysis of the soil gene- 

 rally resting on this formation is as follows, the result being ob- 



