Another characteristic of chalk, which requires careful observation to prevent slips, is that water does not generally issue through a mass, or equally over a consider able area, but is discharged through fissures, and crevices, and flint beds; hence one of the chief means of preventing slips cannot be adopted, namely, to disallow a localization of the flow of any water; therefore, the disturbing element of water seams is in greater or less degree present in all chalk-earth that is not solid and homogeneous in texture. The flow from such water-veins or seams should not be interfered with, as any obstruction, and possibly diversion, which is likely to fail, will only result in the spring saturating the adjacent soil, and in its bursting out at another place. There is no safe remedy but to gently lead away the water, for where springs occur, either in chalk or rock, they will find the line of least resistance; consequently the waters of percolation will tend to flow to one place, and cause a spring. Chalk is found in regularly stratified and separated masses, sometimes caused by beds of flints, and although the position of the layers may indicate their successive ages, age can hardly be taken as an absolute indication of the increased stability of chalk in earthwork. When overlaid with clay it is usually harder than when bare, probably owing to pressure, non-exposure to atmospheric influences, and to the absorbed water being of a different character, which has been proved by analyses. It is especially advisable in chalk soils to know the head level of water in the district, and to note if the bottom of a cutting is below the usual water-bearing line in the open wells, which may not necessarily be at the same depth; their average level being ascertained, an idea can be formed of the probability of springs bursting out, and according as the rainfall is excessive or not, so usually will be the flow. If chalk beds incline across a valley, and have an impervious stratum of clay upon them, it has been found that the most water issues at or about the point where the impervious seam first overlies the chalk, _i.e._, at the edge of the basin, and the greater its depth, the less the flow; therefore, should a cutting be located at a place where this stratum is thinnest, more water from springs may be expected than at any point where the impervious layer is thicker.