Litchfield enquirer., 1854-02-09

water, and a also enables air to be suck- ed tn after the water sit descends thro' the sol, and hence und0ubtedlY carries It. 5th, the air which descends into the soil carriers wilh it a milder temperature. !. c. more caIoricS and gsadually warns the earth through which l, passes.
 a2 Wa'ei in its office of earsiss is called tae 0qaeoWs agent tn the production oI gsolngiUSl formations.
 . Aqueous rocks cover a large portion of the eafth's surface, and are always st'atifed, or divided as before stated into layers which are generally in nenrly 2 horizontal position. though often wavy broken. Or obliqus. Water promotes these vali0us positions by carrying it own elements 10 the support of interna fires: this win be alluded 10 under an, sotber head. They are composed (as be fore saidl of silicious rocks. lquartz. flint, sandstone, etc )argillsceons rocks which include clay. and calcareous rocks which are composed of lims and carbonic acid, These rocks are often blended together and assume tLe forms of siliciuus lime. stone. mari alate, magnesium limestone, gypsum, etc. 8
 . All these formations were once taken up, carried, and deposited by water, and are met with in various forms. We often meet with rounded pebbles and then with layerscf other varieties. inesrati6ed rocks. which slow that they were once deposi- ted by water. The fragments of aquatic animals which aEe found iueoms O! these rocks indicate that they were formed un- der water. either in rivers or oceans. Nor are these rocks tic result Of transient floods. for they form in some cases, the entire mass of mountains. Hence the varied forms of strali6ed rocks. tue diff ferent layers of which may contain dis linct fo,ms of fossils. and are often thou. santls of feet thick, must have been fofm. ed by water Tor they could not have re- suited from any one convulsion. We may infer fIom the comparative lighlness and i ia.ness of lhe va, ioas particles which water carries and tom the different yes iocitics of currents al diffgcnt times, that these distinct strata might have easily been formed. These rocks sometimes contain fresh water shells and fossils. which alternate with thosa of marine ori- gin, indicating that tho ocean and ,iyers alternately deposited the substances they coBiain. There are also excavations near the mouths of various rivers which are held for years by fresh water. and are then broken into by the sea, aud either filled up or enlarged w IN.
 The materials of. meiamorphic rocks (which have since their deposition been modified by hea,) wore originally carried and deposited in the form of sediment by cunning water.
 q But tho farther classification and composition of rocks does not properly belong to the present subject.
 Water is both a destroyer and ( build. or. but inasmuch as it's carrying power enables it 10 accomplish both lhess ends at the same time and with the same ma. teriAls let us consider merely the way in which the materials are obtained and car tried, and some of tho changes which have been recently wrought in thescruss sof the cath. remembering that water has been for ages performing the same part probably on | more extensive scale.
 We have seen that snow and rain act ing both mechanically and chemically. gradually decomposss the rocks ant earth which being loose in the spring ar' easily semoycd and carried by the rain' and the melting snows. and ice of th. mountains. We have also observed the ac.ion of continual freesing and ,hawina and tLe action and effects of glaciers wbils we were considering the subject of soils The effect of meieosic agents are ofter combined with the effect of rivers as wil be seen under the next head. 7. Let ms now observe the action oi rivers and streams in changing the sur> face of the earth. We have spoken oi water as carrier of gases. and hence as n chemical destsoyer Of rocks and earth. We now consider water as . carrier oi maiefials chemically pulvc,ized. and ol those which fesull from the mechanical action of rivers ard torrents. Rivers wear away ihe maltef with which they come in contact, and the extent of this wear depends on the nalure of their bed. and upon the velocity of tho currents. 3
 A force Of iErec inches per second Nill tear up 6ns clay. six inches sill lif fine sand eight inahss, sand as coarse, sl linseed. twelve inches. fine gravel whil. t requires velocity of twenty -fourinchel per second to roll along founded pcbblel an inch in diamsfer. md ibiriy-six inchs, pr. sec0Rd teEkesp along TonDdsd sionel Of inc diameier of . hens egg. ss
 Ppse running water alone will havs iiitIs effect upon had rocks whatever t, velocity. but when t contains pebble, Iand angular stones lhesa seoup out chan. uels in ihesidas aud bottom of lhe ai,eaa l3 q .r s4