98 WEEPING HILL-SIDES. 



sents such a disposition of the strata as has just 

 been referred to. The rain which falls on the tracts 

 of country at (a) and (&) gradually percolates toward 

 the centre of the basin, where it may be made to 

 give rise to an artesian well, as at (c), by boring 

 through the superincumbent mass of clay ; or it 

 may force itself to the surface through the thinner 

 part of the layer of clay, as at (d), there forming a 

 spring or swamp. 



" Again : the higher parts of hilly ground are 

 sometimes composed of very porous and absorbent 

 strata, while the lower portions are more impervi- 

 ous, — the soil and subsoil being of a very stiff and 

 retentive description. In this case, the water col- 

 lected by the porous layers is prevented from finding 

 a ready exit, where it reaches the impervious layers, 

 by the stiff surface-soil. The water is by this means 

 dammed up in some measure, and requires a con- 

 siderable degree of pressure ; and, forcing itself to 

 the clay at various places, it forms those extensive 

 ' weeping'-banks which have such an injurious 

 effect upon many of our mountain pastures. This 

 was the form of spring, or swamp, to the removal 

 of which Elkington principally turned his attention ; 



