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stall and Fountains Abbey, and of our own venerable Parish 
Church, which were wholly built of it, still amply testify, 
but every year a scale exfoliates, an atom daily crumbles 
into dust, as though to indicate its perishable nature. 
The gradual absorption of oxygen by mineral masses ex- 
posed to the atmosphere is another source of decay, the effect 
of which is to disturb the combinations of the elements of 
rocks, and so to pulverize and render fit for soils even the 
hardest aggregate formations. A practice generally prevails 
in this neighbourhood of turning the small mountain rills upon 
the sloping pasture lands below in diverging rays, in such a 
manner as to irrigate the soil, and probably deposit a thin 
alluvial layer, consisting of these particles, together with 
decomposed animal and vegetable matter, for it is found to 
have a very fertilizing effect. 
Much of the physical geography of our district must be 
ascribed to the augmented power of running water. The 
force and velocity of mountain streamlets, aided by the at- 
trition of suspended sand and pebbles, which have often lost 
half their weight when in this dense medium, are such as to 
disintegrate their channels, and cause yawning chasms of 
large dimensions. The precipitous valley rising from Heb- 
den Bridge to beyond Heptonstall, in this parish, affords an 
instance of this kind, in which the wasting power of the 
atmosphere and descending torrents is very conspicuous. 
Composed of alternate thin limestone, plate, shales, and 
gritstone, the strata have presented substances of different 
resisting capabilities to their forces. The gritstone would have 
long withstood their action, had not its base of plate and shale, 
(insidiously worn away by the searching subtle fluid) hurled 
destruction to the superincumbent mass. This alternate grit, 
plate, and limestone district, towards Todmorden, shows many 
holes and cavities in the rocks, and the valley of the Hebden, 
just alluded to, seems to have been scooped out by the ordinary 
