130 The Agricultural Relations of the Western Portion 
The irreu;ular indentations at the junction of this deposit with 
the subsoil, or with the stratum on which it rests, considerably 
embarrass the operations of draining, when the indentations have 
been formed in tenacious clay. Tliey are probably the principal 
cause of the discrepancies of opinion which prevail respecting 
the superior efficacy of deep or of shallow drains.* 
From the combined influence of the most modem tertiaries, 
the warp-drift, and the eocene tertiaries, there result a great 
variety of soils, reducible to three classes — 1, clay, and clay 
loams ; 2, sands, gravels, and sandy loams, on a retentive base ; 
3, sands, gravels, and sandy loams, on an absorbent base. The 
improvement of the first class is to be sought in effectual drain- 
ing and subsoiling, in conjunction with the use of lime, or chalk, 
or burnt clay. The improvement of the second class must con- 
sist in draining, subsoiling, and the addition of chalk or lime, or 
of marl and clay unburnt. For the improvement of the third, 
the chief requisite is the addition of chalk, clay, or marl. The 
liberal use of organic manures is, in each case, presumed. 
Mineral Manures. — Mineral manures are by no means wanting 
in the district. In the gault and greensand, which crop out on 
the western side of the chalk range, and in the Purbeck oolites, 
there are some valuable beds of marl ; but the intervention of 
that steep ridge renders them by no means accessible to the 
tertiary strata on its eastern side. Chalk, the fossil manure most 
used, borders the whole district. At Studland Point, and from 
thence by Dorchester, round by Bere and Wimborne, and from 
the neighbourhood of Lulworth, there appears to be a line of 
fault, by which the hard lower chalk has been brought up 
through the the upper chalk, which has been denuded, the hard 
chalk havinjr been brousrht into contact with the eocene tertiaries 
which abut against it. This hard chalk, though it falls with 
the frost, is too hard to be used on the light soils, except in the 
burnt state as lime. 
On the stiff clays it would probably be more beneficial, by 
imparting friability to them, than the soft chalk. Lime is little 
used as manure. Where used on the newly-reclaimed heath- 
land, great benefit is found to result from it. A portion of 
Rempstone Heath, on the Lower Bagshots, consisting of a light, 
moory soil on a base of clay, has been lately reclaimed by Mr. 
Calcraft. The process of improvement consisted in draining, 
spreading the clay from the drains on the surface, and liming. 
Thus treated, it produces good crops of turnips and roots ; and 
* This passage has been ■written six years. For further information on the 
application of those indentations, which are the transverse sections of subterranean 
furrows, to draining, see Journal of the Eoyal Agricultural Society, vol. xiv. p. 96, 
on the Kcythorpe system of draining. 
