106 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. [Vol.Y. 



The strata at this locality have been much disx)laced, the dip being to 

 the southwestward and at an angle of about 55°. At the southern por- 

 tion of the exposures of the strata of this locality, however, the strike 

 curves to the eastward, so that the dip is then to the southward and the 

 angle lessened ; but the details of this subject will be embraced in Dr. 

 Peale's final report, and also briefly ia Art. VI, i3p. 119-123. 



Section at Locality No. 1. 



A. — Alternating limestones and arenaceous shales ; outcrops obscure. "" 

 The following fossils were obtained fronn near the top of this mem- 

 ber: Tercbratula semisimplex White, T. augusta Hall and Whit- 

 field, Aviculopecten idalioensis Meek, Go-villia ?, and an > 1^ 000 feet. 



undetermined Conchifer. 

 B. — ^Limestones ; outcrops somewhat obscure. The fossils are : Eumicrotis 



curta Hall and Aviculopccten idalioensis Meek. 

 C. — Greenish and reddish fossiliferous sandstones, followed by arenaceous -\ 



shales and limestones. The fossils are : Aviculopecten pealei White > 850 feet, 

 and three or four undetermined species of Conchifers. - / 



D. — Bluish-gray limestones, with fossils near their base. The fossils are : "j 



Meekocei-as gracilitatis White, M. mushbachanusW . , Arcestes ? cirratus i' «/^/^ <? . 



W., Arcestes? ?, Arcestes? (another species), and Eumicrotis ( 



curta Hall. J 



E. — ^Eeddish and greenish laminated sandstones 400 feet, 



F. — Very dark blue limestone } oqq ^ , 



G. — ^White quartzite ) 



H. — ^Massive grayish-blue limestones 400 feet. 



At locality No. 2, which is about fifteen miles a little east of south 

 fi?om locality ISo. 1, occurs another limited exposure of limestone strata, 

 which are equivalent in part with those of locality JSTo. 1, and which 

 there occupy a synclinal axis. From these strata, Meelcoceras aplanatum 

 "Wliite and M. gracilitatis W. were obtained. The presence there of the 

 latter species indicates the equivalency of those strata with member D 

 of the foregoing section, because numerous examples of that species 

 were obtained from that member of the section. 



About the same distance as before (15 miles), almost due west from 

 locality No. 1, is locality No. 3, the strata being calcareous sandstones. 

 From these strata, Dr. Peale brings Aviculopecten idalioensis Meek and 

 A. alius White, examples of the former species being somewhat abundant. 

 This species occurs in both A and B of the foregoing section, with which 

 members the strata of locality No. 3 are doubtless equivalent. Mr. Meek's 

 types of this species, which he referred to the Jurassic, Avere obtaiaed 

 several years ago by Dr. Peale in Lincoln YaUey, near Fort Hall, about 

 fifty miles northwestward from locality No. 1. So far as I am aware, 

 the species has not been discovered elsewhere, and it may therefore be 

 regarded as a common associate of the Cephalopods herein described. ~ 



The relations of the strata of the three localities here discussed with 

 those which j^recede and follow them in natural order have not been so 

 completely studied as could be desired, but Dr. Peale regards members F, 



