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forms of vegetable life, nothing is more pernicious than a putrid pool ; 

 those shrubs and trees, therefore, which are thus attacked, root and 

 branch, perish and fall, adding their decaying limbs and leaves to 

 tlie increase of the destructive powers now in full operation. Minor 

 streams overflow in the same neighbourhood, acted upon by similar 

 or collateral causes ; and where a luxuriant verdure once gladdened 

 the woods, the lapse of a few years shows extensive tracts covered 

 with blackening vegetation, and emitting those unhealthy exhalations 

 which the naturalist finds it his best interest seriously to guard against. 

 But, once formed, this marsh has become a fit soil for the propagation 

 of plants peculiarly adapted to it, which rise and fall in their appoint- 

 ed seasons, gradually, though slowly, increasing the thickness of the 

 mass of decayed vegetation. In course of time, the land becomes of 

 too solid a texture, by reason of the deposit both of carbon and of 

 mineral soil from chemical and alluvial causes, to support its old de- 

 pendants, and a new race slowly springs into life, — in our climate 

 principally heaths ; in South America, chiefly species of Cactus, and 

 enormous grasses and Cyperaceae. These are precisely the causes 

 distinctly seen in operation in some of the finest districts of Ross and 

 Inverness. 



The usual composition, therefore, of the peat of our fens and 

 marshes is Sphagnum, and every aquatic plant, the inferior layers of 

 which are always densest, on account of the great weight of the super- 

 incumbent mass. Such extreme density, indeed, is attained in some 

 cases, as to form a substance convertible into ornaments resembling 

 jet, and susceptible of a fine polish. 1 have seen beautiful sections, 

 though only six to eight feet in thickness, of the peat soil in the 

 great Amberley Wild Brock, in this vicinity, in which the fineness 

 of the texture of the lower peat, clearly demonstrates the efilcacy of 

 the decomposing process which has acted on it for centuries. A key 

 to the rate of the increase of bogs might be afforded by the discovery 

 which a labourer of Nutbourne made several years since, of an ancient 

 British lance-head, constructed of copper, buried to the depth of seven 

 feet in a marsh near Pulborough. This relic was lately in the pos- 

 session of a gentleman at Storrington, since deceased, and has since 

 passed into other hands. The depth of eight feet would give a very 

 slow rate of increase indeed, far less than that of twenty inches in 

 sixteen years, assigned by Mr. Jenyns to the turf of the Cambridge- 

 shire fens, and w hich seems to be unaccountably rapid ; but it must 

 also be taken into account that this peat marsh has pretty frequent 

 demands made upon its contents by the turf-cutters, as well as by the 

 Vol. II. 2 y 



