82 IMPROVEMENT OF THE SOIL 



vailing rock here is gneiss, with occasional beds, or 

 veins, of hornblende, greenstone, and sienite. About 

 five miles to the north of us is the great valley of transi- 

 tion limestone, stretching from northeast to southwest, 

 and immediately on the northern side of this valley, run- 

 ning parallel with it, is a broken ridge of hills, formed of 

 mica slate, — with beds of serpentine rock and hornblende, 

 on the side next to gneiss rock, on the southeast. 



Over the gneiss rock, and among the hornblende, the 

 soil is generally a still loam ; and I think the best effects 

 are perceptible from a given quantity of lime. On the 

 soil overlaying the schistose rock, the good effects of 

 lime are sufficiently obvious, under the management of 

 skilful farmers ; but the benefits seem to be less perma- 

 nent. 



On the serpentine rock the soil is extremely sterile ; 

 and neither lime nor barn-yard manure can be used with 

 much advantage. In the limestone soil of the great val- 

 ley, where one would suppose it was already redundant, 

 lime is used whh advantage ; and much heavier dressings 

 are put on, than in the adjacent districts. I cannot fur- 

 nish the rationale of this practice, but I believe the fact 

 is established, that more lime is required to produce the 

 same beneficial effect on soils resting on limestone rock, 

 than upon those overlaying gneiss, and perhaps some other 

 primitive rocks. 



I have had no opportunity to witness the effect of lime 

 upon secondary^ and strictly alluvial, formations ; but 

 the circumstances have led me to suspect, that the same 

 quantity of lime would not be so signally beneficial in 

 secondary, as it is in certain primitive formations. 



Lime undoubtedly has a good effect in soils which are 

 sandy, even where sand predominates ; but I beheve its 

 mehorating properties are most conspicuous in a clay 

 soil, — or rather in a stiff loam. A good proportion of 

 decomposed vegetable matter adds greatly to the benefi- 

 cial effects of lime ; and hence our farmers are desirous 

 to mingle as much barn-yard manure as possible with their 

 lime dressings, — and to get their fields into what is called 

 a good sod, or turf, — full of grass roots. Then a dres- 



