Show characteristic EROSION IN JURASSIC SANDSTONE in zion canyon the vertical cliffs of vermilion sandstone are surmount eur mount ed cd by huge caps and pinnacles of white to yellow sandstone Band stone both constitute what kimt la Is known geologically as aa navajo sandstone within these cliffs horizontal surfaces slopes and walls cross crosa bedding Is vis ible to a remarkable degree tle gree cross bedded of Ir frozen rozen saud sand often appears ca huge inclined area arcs which gradually decrease as they merge into underlying layers huge sweeps of sand extend from to feet to join or cross sma eme elm swee sweeps ps that form loops and arabo araba tho the prevailing design best visible in majestic mountain and oil 1 zion carinel hill Is composed compo ael ot 01 curves tangent to curves just below the tha navajo clien 1 Is 14 4 a ledge ot of horizontal layers of 0 isop bedded dull re vanstone ean san stone charleter j iced by regular block like fractures called by some the upper chinle there Is come question as aa to whether this la Is upper tipper chiglo or it represents ledges of sand that wera deposited under sha shallow ilow water supposedly during the early jurassic period wind water and variations in daily temperature have caused the exposed surfaces to frae fraiture ture and orl or l odo ode fracturing Is both vertical and I 1 horizontal and uto the blocks formed ore are square or recta rectangular figular to slightly irregular and moderate in size compared with the hugo huge blocks tha split off from arout the surmounting navajo the final appearance Ls la like that of 0 man mail made masonry navajo sandstone la Is characteristic wind blown sand that was formed over ci a vast plain or deser deceit t in on early eaily geologic period wind swept deserts of shifting shit ting sand dunes 2000 to feet deep extended from south western colorado Coloia do to southern nevada gradually Gia dually this tIll vast t area sank through the downward ra movements of the earths crust until they like other deposits below them became engulfed by the encomb incoming g waters of one of the opi continental seas that at intervals previously had P tilfred this great inland region lime and other cementing were amhed over the surface of sand and slowly with the aid of pressure and long periods of time these cheso shift ing ng lesert desert and sand dunes were vere sot sol to hard white and vermilion 1 sand rock I 1 navajo sa sail natone stone la Is a typical cliff maker the vermill vermilion rock has a tell tendency dencY to split in long vertical or dur villear fracter frac tur parallel to tha surface of the cliff and parallel to the cross bedding lamin pe an erosion slab Is produced with curved faces leaving a sheer wall of slightly curved surface behind smaller thin pieces scale le oft off from the cliffs and canyon walls these are especially evident in the region of weeping rocks where water seepage has aided temp pilaf changes cli anges in producing this type of fracture in contrast to the vertical fractures trac turca of the vermilion layer of navajo s sandstone in the surmounting crests of tho the white cliffs r piear as smooth slid surfaces surface eroded to hard peaks and pinnacles weathering has produced surface cracks in places but fractures ledges and bridges are not characteristic te tho the surfaces am afo more often curved than vertical 1 the ate pinnacles precipitous and the area the caps of white are ara often coap shaped sha shi ped they lie over the vermilion cliffs and are ard often surmounted with a small ledge of red producing a fantastic effect when viewed vl omAl front from a dia diatto the guardian angels in the west canyon arre or of this structure ur 0 a and d r remind e mi n d 0 one ne of huge d dishes 1 ashes of ice cream the colors of the white and ver millan cliffs are chiefly due to the tha kinds of cementing substances the white cliffs have only calcite cacos cement except where iron oxides from overly red ledges have washed over the surf roo the vermilion sandstone varies from ye yellow llovy butt buff and tan to red tones and Js Is due to the degree of concentration of iron cc compounds im iron in genarah genara gen sra the llo cement la Is lime cacos cd dolomite cacos with varying degrees of iron magnesium copper and other substances cementing an aggregate te or of white crystal clew quartz grains erosion factors are many in i but the outstanding effects on the upper strato strata of sandstone are ard three folds fold in the upper chi ale ledge below the navajo block like fracturing appears in the vermillon vermilion cliff a per cular parallel splitting that leaves vertical cliffs and arches in tile the white a 0 slow surface erosion to form cones curved surfaces sur facea kind pinnacles with an absence of noticeable noti cable fractures |