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Show ORGANIC REMAINS IN PEAT. ~no (Ch. XIII. . . anently covered by water, of the surface whiCh lS not perm dl the manner in which lakes . secon y' whether of the sea or . 'dd d . sub-aqueous deposits. orO'anic remam· s b eco me . tm. be e hm · 11 treat of the followmg o d' Ion we s a Under the first IVIS t and the preservation of h owth of pea ' topics :-1st, t e gr . h ·n ·-~ndly, the preserva- . l emams t erei ' vegetable and amma. r. 1 ft and in the mud of caves . l mams m sta ac 1 e, . . 11 tion of amma re . f organic remams m a u-and fissures ;-Sdly, the burdyml~ 0 ·-4thly of the same in · of Ian -sIps ' ' . vium and the rums 1·n volcanic eiectwns, and hl f the same J blown sand ;-5t y, 0 · roductions. alluvions composed of volcamc p The growth of P ea t an d the preservatio.n of Vegetable and Animal Remains theretn. f of peat wh en not completely under .w ater, THE genera ton . ' . here the temperature IS low, . fi d t oist sttuatlons, w . . I lS con ne o m d mpose without putnfymg. t and where vegetables may eco plants which are capable . f of the numerous may consist o any . . b t a species of moss (sphagnum · · uch statwns · u · of growmg m s 'd b1e part of the peat found m ) t. t tes a const era palustre cons 1 u . this plant having the pro· marshes of the north of Euhropte '. t'ts upper part, while its h · up new s oo s m perty of t rowmg . ~ Reeds rushes, and other lower extremities are decaymg . . d .' peat and their all be trace m ' aquatic plants may usu ~ l t there is no difficulty in orgam. zat t'on is often so entire., t la discriminating the distinct spectes. h dred parts of dry peat s· H Davy one un In general, says tr . . ' t f matter destructible . t · ety-nme par .s o contain from stxty o nm . f ths usually of the same by fire, and the residuum conststs o lear 1 or rock on which kind as the substratum of clay, mar 'r ~ave '" The peat of the h 'th ideo uon. they are found, toget er Wl ox the same writer, ''con· E 1 d " observes chalk counties of ng an ' .r d very little in any tains much gypsum.' but I have 1oun . t 'b te to the generat i.O n of peat ' see * For a catalogue of th e p1a nt s wh1ch conunll u b'a Western lsles, vol.l·· P• 129 • Dr. Rennie on Peat, P• 171 - 178 ' Dr, Mace oc ,. Ch. XIII.] AREA COVERED BY PEAT. ~li specimens from Ireland or Scotland, and in general these peats contain very little saline matter*." From the researches of Dr. Macculloch, it appears that peat is intermediate between simple vegetable matter and lignite, the conversion of peat to lignite being gradual, and being brought about in a great ]apse of time by the prolonged action of watert. Peat is sometimes formed on a declivity in mountainous regions where there is much moisture, but in such situations it rarely if ever exceeds four feet in thickness. In bogs, and in low grounds _into which alluvial peat is drifted, it is found forty feet thick and upwards, but in such cases it generaUy owes one-half of its volume to the water which it contains. It nas seldom, if ever, been discovered within the tropics, and it rarely occurs in the valleys even in the south of France and Spain. It abounds more and more in proportion as we advance farther from the equator, and becomes not only more frequent but more inflammable in northern latitudes! ; the cause of which may probably be that the carbonic acid and hydrogen, which are the most inflammable parts, do not readily assume the gaseous form in a cold atmosphere. There is a vast extent of surface in Europe covered with peat, which in Ireland is said to extend over a tenth of the whole island. One of the mosses on the Shannon is described by Dr. Boates to be fifty miles long, by two or three broad; and the great marsh of Montoire, near the mouth of the Loire, is mentioned by Blavier as being more than fifty leagues in circumference. It is a curious and well-ascertained fact that many of these mosses of the nort~ of Europe occupy the place of immense forests of pine and oak, which have many of them disappeared within the historical era. Such changes are brought about by the fall of trees and the stagnation of water, caused by their trunks and branches obstructing the free drainage of the atmospheric waters, and giving rise to a marsh. In a warm climate such decayed timber would immediately be "' Irish Bog Reports, p. 209. t System of Geology, vol. ii. p. 353. ;I: Rev. Dr, ReDDie1 ibid. p. 260, P2 |