Valley land is not good if it is _perfectly_ flat. It will then be subject to inundation and stagnant water. There is nothing that kills the plant so surely and quickly as the latter. Even quite flat valleys can be made sweet by artificial drainage, but to do this a lower level, not too far distant, must exist, and the danger is not quite removed then. Valleys in which no water-course exists, and which slope towards the mouth _alone_, are to be avoided, for the plants near the mouth always get choked with sand. The best valleys are those with a gentle slope both ways, one towards the lowest line of the valley, be it a running water-course, or a dry nullah which carries off rain, the other towards the mouth of the valley. Such valleys drain themselves, or at least very little artificial drainage is necessary. A valley of this kind, with a running stream through it, is _most_ valuable for Tea, and if the other advantages of soil and climate are present it is simply a perfect site. Such however are not frequent. If in such valleys, as is generally the case, the slope from the head to the mouth is enough, the running stream can be “bunded” (shut up) at a high level, and brought along one side at a sufficient elevation to irrigate the whole.
I have never seen but one garden in a valley that fulfils all these conditions exactly. It is in Chittagong; the soil is good, labour plentiful, and manure abundant. It ought to do great things, for the possibility of irrigating plants in the dry season (which, as observed, is very trying in Chittagong) will give several extra flushes in the year.
Of course in the wet season on such land the water must be allowed to resume its natural course.
Narrow valleys are not worth planting. No narrow tracts of land, with jungle on both sides, are worth the expense of cultivation, for the continual encroachment of the jungle gives much extra work. The plants, moreover, in very narrow valleys get half-buried with soil washed down from the adjacent slopes. Narrow valleys are therefore, in any case, better avoided.
To conclude shortly, flat lands can be highly cultivated, steep slopes cannot. Tea pays best (perhaps not at all otherwise) with high cultivation--_ergo_, flat lands are preferable.