250 W. N. LOGAN 
horizon. The beds consist here as elsewhere of alternating beds 
of sandstone, shales, and limestones. 
In the Lincoln Basin the following Jurassic fossils were col- 
lected: Ostrea strigilecula,; Belemnites densus,; Pentacrinus, Ostrea, 
Gryphea, Camptonectes, and Pseudomonots. 
At Meridian Ridge Peale* found 150 feet of bluish and gray 
limestones ; bluish laminated limestones and bluish argillaceous 
shales and slates followed by 100 feet of reddish sandstone and 
bluish limestone containing Pentacrinus astericus ; Ostrea strigilec- 
ula, Camptonectes bellistriatus and other forms. This thickness of 
250 feet doubtless represents a conservative average for the 
SnibineNCiSimct 
On the John Day (Gray) River? the following fossils were 
collected: Pentacrinus astericus; Belemnites densus; Camptonectes. 
bellistriatus ; Gryphea, Trigoma, and Pleuromya; and from another 
outcrop, Pentacrinus astericus ; Ostrea strigilecula, and Tancredia sp. 
An outcrop in the Sublette Range furnished Pentacrinus astericus 
and Camptonectes bellistriatus. 
The Jura at Bear Lake Plateau3 contains Pseudomonotis curta 
and other forms. The fossiliferous beds consist of 90 feet of 
gray limestone and 80 feet of bluish-gray limestone with bands 
of sandstone. This group rests on 150 feet of limestone which 
may also be Jura but there is no faunal evidence of its age. 
On Bear River in Southwestern Wyoming Meek‘ gives the 
following section for the Jura: ‘‘ Ferruginous sandstone, in thin 
layers, dipping northwest about 80° below horizon, 40 feet; 
bluish laminated clays with, at top (left or west side), a two- 
foot layer of sandstone containing fragments of shells not seen 
in a condition to be determined, 125 feet ; Clays and sandstones, 
below (20 feet); gray and brown pebbly sandstone above (25 
feet), 45 feet; brownish and bluish clays, with some beds of 
white, greenish, and brown sandstone, 115 feet.” From the 
second layer the following fossils were obtained: Belemmnites 
™ Ann. Rep. U. S. Geol. Surv., Vol. XI, 1877, p. 536. 
2 Ibid. p. 544. 3 Ibid. p. 585. 
4Ann. Rept. U. S. Geol. Surv., Vol. VI, 1872, p. 451. 
