Show mighty aty falls of niagara are crumbling each year tile the mighty falls of niagara are crumbling year by year as thousands of tons of roh rock crash from the up lip of the gorge by the year the waters will have completely worn away the falls and there will be only the he 10 mile river running down a cascade dotted bed from lake erie to the great gorge of niagara the recent fall of tons of rock was symptomatic of the gradual erosion but bul this incident was only one of a series of crashes that began thousands of years ngo ago nature Is a sculptor who never stops working and one of her greatest molding and remolding weapons Is water visitors now see two cataracts the horseshoe falls on the canadian side and the smaller american falls but once there was only one cat cataract ilmet geologists estimate that niagara falls fails Is years old Iron ironically leally the process of nature that formed the falls Is now working steadily but with almost inconceivable slowness to level them the recent crashing of tons of rock was only one comparatively tiny stop step in this till never ceasing process in one way the manner of de destruction used by nature in niagara falls Is unusual all the cataracts on the earth have been formed by the wearing away of rock roca by water the sand and gravel usually swept along in the water helps in the cutting work when there Is a tilt in the river bed or different kinds of rock present ras cades and sometimes waterfalls are created nut but the water in ninga ru j river lowing flowing from lake erie Is re marh mar ably kably clear in it there ts Is practically no sand or gravel scientists have discovered that alio 6 top layer iner of the escarpment Is of liard hard dolomite with soft shale be i neath this explains why largo large pieces of the top rock roch break off the water erodes the shale gradually tearing the support from un der the dolomite which then crashes down own but it breaks off in such a way that the walls of the falls are left unimpaired ris as yet cut but little by little the dolomite at the creat which forms the lip over which the great lakes pour their stupendous excess water supply Is disappearing though it Is difficult to estimate the rate at which the wn wall 11 la Is receding and the gorge at the same time la Is lengthening scientists set the figure nt at 37 feet per year this Is how they arrive at the con conclusion chislon that it will take until the year before the 10 miles of rock between ulm lake erle arle are completely broken down |