Show earthquakes in the december number of the F forum bruni major J I 1 V powell die dis cusses at length the cause of earthquakes As a preliminary to his exhaustive treatise on the subject the writer explains what the I 1 geologists means by geologic formations in such a manner that they may nay be pe clear clearly I 1 aseen seena I 1 i n the minds winds eye ae As an example exar opla ho he selects De aiSea and his p tion of that peculiar body of water may broye interesting to the read era of the HERALD great salt lake saye says bajor powell lies upon the western elope slope of the wasatch Blount mountains ains into it flow the bear the weber and the jordan rivers and many smaller streams et reama all these streams ahei are at flood tide loaded with sand and amud kiich they carry into the great salt lake and which are deposited in its bottom the rains rains i which are gathered into streams also dissolve much of the rocks of the ibe adjacent mountains and valleys and all of this material held in soi lution is carried into the lake and and precipitated the lake isi ie there fore filling up slowly when me measured in terms of human bi history stori but rapidly when measured in terms onearth of earth history that is when considered froni from a geologic standpoint this process has been going on for hundreds perhaps thou sand sands of years and seem likely to continue until the jake lake is entirely filled when this is accomplished I 1 abed a great sheet of band and mud will be spread over a broad plain within this sheet there will be layers and beds of salt gypsum and other material and it will contain the shells of animals liv living ing i in in the lake those washed into it the bon bones of other anim animals alst and the shards and skeletons of insects it will also contain the leaves leaved limbs and trunks of trees and vestiges of many smaller plants now such a sheet of dep deposits is a it geologic formation through a long period a of the ear earths ilis history it may be very greatly changed it may be con soli dated into indu rated beds it may be broken int into fragments tilted into ridges and the ridges themselves may be worn by rains and rivers into hills and rind valleys in such a mand manner er that a hilly or mountainous region may be found on the present site of great salt lake lakeland and should it then be st studied by the geologist the salt lake like formation will be described and characterized in every lake and inland sea of this country and the world like geologic formations I 1 are jn in process of construction great sheets of rock are washed wo them by rains I 1 a and n d rivers and di deposited in their quiet waters the thi great salt lake now but a small sheet of water but many ce centuries i f ies ago it was much larger and spread over a long lone and slid broad valley most of which is now dry jand jaud this ancient body water ia is called by geologists lake bonneville its old shoreline shore line has been deformed so that some portions port ione of that continuous line now one bundel and fifty feet higher than other portions oue all 01 duo to die displacement plAcement displacement major powell ar gue gues is the cause of earthquakes and bis his conclusion has been reached by a careful e examination of the conditions attending the tha earthquakes of which tb there ere ie is any ady record prom from the literature of the subject i of earthquakes the following inferences the major sa says a seems to be derived 7 J i first if we entirely neglect all geologic evidence and recur solely to the evidence given by the waves of motion of earthquakes the I 1 locus of origin is is shown to bo be thousands ol 01 feet beneath the surface second the tle centrum or place oi 4 origin is not small and well welt defined as would be a cavern but is ir rather a district extending many miles A along into the depths of the earth third it seems probable that the medium I 1 through which waves 7 are os bitted to a great distance diet noce in is the iyub ab cruet crust a somewhat homo hom genous body of ot rock as above elde de scribed ascribed bed fourth it seems probable that after passing some distance from tho the locus of displacement placement die or the centrum of the earthquake the formund form und character of the wave waves brought to the depend upon ibo the characteristics ice of the structural crust and the conditions under which the alv waved wave are tike akell t up from the tho aub crus fifth the chief destruction wrought by earth quakes io 0 duo due lo 10 derived and greater transformed motions roo tiona in minor iu eu f |