Indications of Fertilitu or Barrenness of Soils. 
575 
like the shape they now have assumed in the tabular forms in- 
serted in different parts of this essay. 
Fertile arable lands are those which are so constituted and 
situated as to produce all the ordinary crops of the farmer in 
abundance, with the usual cultivali(m only. The vegetation on 
arable lands will be, or ought to be, unless such lands are fallow, 
the crops which have been sown upon them by the farmer, and 
cannot be depended upon as indications with safety. Their 
appearance may assist, but must not be considered to be suffi- 
cient. Soils of a medium and inferior quality, which are ob- 
served to produce as good crops as naturally fertile soils, are 
made to do so by cultivation, and their fertility is only apparent ; 
and they must not, under the sense to which we have limited the 
term, be denominated fertile. Their fertility is due to cultivation, 
and not to natural causes. Considerable difficulty may here arise 
in distinguishing how far their apparent fertility is due to cultiva- 
tion. The best tests are geological position, the subsoil, the 
natural herbage at the sides of the fields, the timber in the 
hedgerows, and the elevation above the level of the sea : the 
surface-appearances are altogether inadequate. Certain geolo- 
gical formations are ascertained to be more productive than 
others, and I have from observation satisfied myself that this is 
no vague theory ; but, further, that some of the formations are 
composed almost entirely, with slight exceptions, of either barren 
or fertile soils. If so, what an important test we have hitherto 
neglected ! And I imagine enough has been said to induce us 
to admit that the natural herbage and plants which may have 
elected to grow on the parts of the fields where the sward is 
untouched by the plough, will afford another strong jjroof of 
barrenness or fertility; and the stunted or luxuriant growth of 
the timber and the thorns in the hedgerows may also be a 
guide; and, lastly, at great elevations above the level of the sea 
but few corn- crops ever arrive at maturity, and are late in being 
harvested. Fertile soil always ripens its crops early. 
The following is a Table, Avhich has been drawn up from 
observations made during a series of years, commencing with 
1826, and continued up to the present date. To exhibit it is only 
to show its imperfections, but I have had abundant opportunity of 
satisfying myself that it is calculated very materially to assist the 
judgment, and to afford information, if rightly applied, which can- 
not be drawn from any other source, not even from geology itself. 
It will be desirable to understand that it is not meant that any 
single species of the natural grasses, here tabulated, will, if found 
alone, be sufficient to warrant us in predicting a future abundant 
crop, but simply that its presence, wherever found, is an indica- 
tion of fertility in the soil that produces it. It is well known 
that, to constitute a good permanent pasture, there must be a 
