Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/19

 and exposure, are still covered with unprofitable heath and peat, producing a scanty and almost useless Herbage. It is worth our while to inquire into the causes of this difference, and to see if valid ones cannot be assigned.

In the land already under tillage it is obvious that the subsoil is covered with a soil actually in use, consisting of vegetable mould annually loosened by the spade or plough, and admitting the penetration of light, of air, and of water, to the subjacent and half decomposed matter. In the uncultivated neighbouring tracts we shall on the contrary find it covered with a thick mass of peat, the immediate soil on which the heath, the sphagnum, the carices, and the rushes alternately flourish and die, adding fresh matter to this already impenetrable substance. Neither air, light, nor water can make their way through this dense covering of a substance so notoriously impervious that it has been found of equal use with clay in puddling the artificial banks of canals. It forms in fact an adventitious and useless soil so entire and so impenetrable that it would be of equally little consequence to the land-owner in its present state, whether it where bedded on a rock of solid quartz or on the most fertile garden mould. Fortunately this covering of peat is rarely so deep that the plough or the cashrom (the crooked spade of the Highlanders) cannot reach to the bottom of it. The remedy and obvious method of improvement is pointed out by the relative condition of the fertile and the barren parts of this tract. The few experiments which have been tried have proved eminently successful, and among them I may point out those performed by Mr. Macpherson at Portree. By the admission of air and water the progress of decomposition is accelerated, and the rock is reduced in no long space to a useful soil. The texture of the peat is at the same time loosened by its admixture with the decomposed rock, and being thus