STRATIGRAPHIC SECTIONS IN UTAH AND ARIZONA. 



63 



that in the eighties supported several flourish- 

 ing mining enterprises.'" 



The mauve cHfl-forming sandstone is the 

 "mauve sandstone" of Huntington and Gold- 

 thwait.''' These authors give the tliickness of 

 the Cliinle (tlieir "Painted Desert formation") 

 near Toquerville as only 350 feet, though they 

 seem not to have included the beds above the 

 mauve sandstone. Lee '- observed at a locality 

 near Cedar City, Utah, 520 feet of red shale and 

 sandstone resting upon the Shunarump con- 

 glomerate, overlain by 250 feet of massive 

 cross-bedded sandstone, and that in turn by 

 180 feet of sandstone and red, purple, and gray 

 shale, a total of 950 feet. In a later report ^' 

 Lee placed only the lower 520 feet of this 

 series in the Chinle formation, but the entire 

 950 feet evidently roiTesponds to our Chinle 

 formation, which is included between the mas- 

 sive sandstone described below, whose basal 

 part, at least, is probably equivalent to the 

 Wingate sandstone, and the Shinarump con- 

 glomerate. LongweU'''' refers to the Chinle 

 formation in Nevada as a variable assemblage 

 of conglomeratic sandstone, finer sandstone, 

 and gypsiferous shale. Its .thickness ranges 

 from 800 to 3,000 feet. 



Walcott found in Kanab Valley a fossiliferous 

 zone '■'' about 900 feet above the Shinarump 

 conglomerate, which seems from the descrip- 

 tion to be near the top of the Chinle formation, 

 though possibly it is in the base of the overlying 

 sandstone, which is not as massive as it is far- 

 ther west. The fossils were fish and reptilian 

 teeth, Estheria, and a fragment of an ammo- 

 nite and are said to suggest Jurassic rather 

 than Triassic relationship. 



JTJRASSIC SANDSTONE. 



Gregory ^^ assigned tliree formations in east- 

 ern Arizona and western New Mexico to the 

 La Plata group — the Wingate sandstone below, 



'» Butler, B. .S., and others, Ore deposits of Utah: U. S. Geol. Survey 

 Prof. Paper 111, pp. 5.S2-594, 1920. 



" Huntington, Ellsworth, and Goldthwait, J. W., The Hurricane 

 fault in the Toquerville district, Utah: Harvard Coll. Mus. Comp. 

 Zool. Bull., vol. 42, p. 203, 1904. 



" Lee, W. T., The Iron County coal Qeld, Utah: U. S. Geol. Siuvey 

 Bull. 316, p. 362, 1907. 



"^ Lee, W. T., Early Mosozoic physiography of the southern Rocky 

 Moimtains: Smithsonian Misc. Coll., vol. 60, No. 4, p. 22, 1918. 



«• Longwell, C. R., op. cit., p. 51. 



" Discussed in Cross, Whitman, and Howe, Ernest, Red Beds of south- 

 western Colorado and their correlation: Geol. Soc. America Bull., vol. 16 

 pp. 486-487, 1905. 



•• Gregory, H. E., Geology of the Navajo country: U. S. Geol. Survey 

 Prof. Paper 93 p. 52, 1917. 



the Todilto formation in the middle, and the 

 Navajo sandstone above. The Wingate sand- 

 stone is a massive cross-bedded fine-grained 

 cliff-forming dark-red to light-red or orange-red 

 sandstone, in which the cross-bedding is largely 

 tangential and gives rise on weathering to char- 

 acteristic arches and caves; its thickness ranges 

 from 200 to 500 feet. The Todilto is a very 

 thin formation of calcareous sandstone and 

 limestone, barren of fossils. The Navajo sand- 

 stone is tangentially cross-bedded massive yel- 

 low to red sandstone with a few thin layers of 

 blue limestone. It is resistant and cliff-forming 

 and usually weathers into domes and rounded 

 forms at the top; its thickness ranges from 100 

 to more than 1,000 feet. The whole group 

 ranges from perhaps 400 feet to well over 1,000 

 feet in thickness. 



In Washington Coimty, Utah, there lies 

 above the Chinle formation a massive cross- 

 bedded sandstone that is locally all red but in 

 most places red in the lower part and white 

 above, the red portion making up one-half or 

 more of the unit. The lower part character- 

 istically forms arches, and the upper part 

 weathers to rounded pinnacles and domes. 

 (See PI. XI, A, B.) \J\Km this white sand- 

 stone rests a series of brick-red sandstone and 

 shale perhaps 200 feet thick. This unit is soft 

 and is conspicuous only where it is left as ero- 

 sional remnants on the white sandstone. It 

 seems to belong rather to the succeeding unit 

 than to the sandstone. Only one measure- 

 ment of the thickness of the sandstone was 

 attempted, and that with rather unsatisfactory 

 results. Tliis measurement was made by tri- 

 angulation from Coalpits Wash, just west of 

 Zion Canyon, on the west side of the AVest 

 Temple of the Virgin, or, as it is locally known, 

 Steamboat Mountain, and gave a total thick- 

 ness of 2,100 feet, mostly in sheer wall. There 

 appears here to be no break of any kind in the 

 sandstone wall; not even a single soft layer is 

 observable. Farther east, toward Kanab, 

 Utah, the sandstone is less massive and con- 

 tains softer layers. To the west, near St. 

 George, Utah, the same is true; in fact there 

 appear to be many softer layers, and the sand- 

 stone forms a number of benches. Northwest 

 of St. George, in the valley of Santa Clara 

 Creek, the unit again takes on a massive clifl- 

 forming character and stands in high, sheer 

 walls with the top weathered into rounded 



