56 



SHORTER CONTRIBUTIOXS TO GENERAL GEOLOGY, 1»21. 

 Gcdoi/ir /(iniKilionx of southwcslini T'tith and northii'istiTn Arhonii — Continued. 



System. 



Carlioniferous. 



Series. 



rermian. 



Permian i '.'). 



Fiirmation. 



Kaibah lime 

 stone. 



Member. 



Harri s b a r g 

 gypsiferous 

 member. 



( " o (^ o II i n < I 

 s.iiulslnne. 



Pennsy^'a- Supai forma- 

 nian (?l. tion. 



Pennsy 1 v a- 

 nian. 



Mississippian. 



R e d w a I 1 

 limestone. 



(iharaeter of rocks. 



Gyp.siim, shale, and limestone, with platy 

 chert. Locally the '■ Bcl.lerophon lime- 

 stone" at top. 



Thickness 

 (feet). 



0-280 ± 



Massi\'e clilf-forminjj clierty gray lime- 

 stone, with locally a thick limestone 1S5-4.55 

 breccia in lower part. 



Soft beds resembling basal member. 



Massive gray limestone with much chert. 



,SO-285 



G ypsiim, gray and yellow shale, soft gray 

 sandstone, and some thin-bedded darli- 

 dr-dh limestone. 



Deep-yellow to buff sandstone at top 

 locally; ma,ssi\'e white frial)le sand- 

 stone in middle: i)ale-yellow sandstone 

 below. 



150-230 



0-100 



90 ± 



Brick-red sandstone and shale in the 

 southeastern part of the region, chang- 

 ing northwestwaril into a yellow mas- 

 si\'e sandstone with only patches of 

 pink color. 



1,300-1,500 



L>ense siliceous gray limestone, with 

 some sandstone layers; mostly heavy 

 bedded; light gray on fresh surface, 

 dark gray and Ijrown on weathered sur- 

 face. 



1,500± 



As the field work dealt chiefly with tiie for- 

 mations between the Redwall limestone and 

 the Shinarump conglomerate the larger part 

 of this paper pertains to them. The fossils 

 collected all came from the Kaibab limestone 

 and from the Rock Canyon conglomeratic 

 member and Virgin limestone member of the 

 Moenkopi formation. They were submitted 

 to G. H. Girty for examination, and the iden- 

 tifications supplied by him, as well as a state- 

 ment of their bearing on the stratigraphy, are 

 inclu(l(ul in the appropriate places. 



REDWALL LIMESTONE. 



The Kedwall limestone was seen in the Vir- 

 gin River narrows (section 19, p. 75) below 

 St. George, where more than 500 feet of it is 

 exposed east of a fault on the cast side of Heber 

 Valley. It is a dense siliceous gray limestone 



with some sandstone layers, mostly heavy- 

 bedded, light gray on the fresh surface and 

 red-brown and dark gray on the weathered 

 surface. About 200 feet beneath the top there 

 is a thin-beilded, very dark gray, higlily silici- 

 fied limestone layer 20 feet thick. This rock 

 has been thought by the residents of the region 

 to contain petroleum, but it does not respond 

 favorably to any tests. A few fragmentary 

 fossils were seen but none collected. The cor- 

 relation with the Redwall limestone of the 

 Grand Canyon district is made on stratigraphic 

 position and lithology. 



Tlie limesttine was examined again at a 

 locality 2 miles north of the Apex copper mine 

 and about 20 miles west of St. George (section 

 20, p. 76), near the pass where the Arrowliead 

 Trail to Los Angeles cuts through tlie Beaver- 

 dam Mountains. In tliis locality the upper 



