562 DESCEIPTIVE GEOLOGY. 



ingly rare but not a unique occurrence, they having been observed in rhyo- 

 lites from both Hungary and New Zealand.^ 



Dixie Group Region. — East of the foot-hills of the trachyte hills is an 

 outcrop of uplifted Tertiary extending from Dixie Valley southward for 8 

 miles, and occupying a valley, or rather a low ridge, between the trachytes 

 and a body of Lower Coal-Measure limestones . to the east. For the most 

 part, they are finely-bedded calcareous shales and marls containing carbo- 

 naceous seams and brown carbonaceous zones, which carry more or less 

 coal. In the calcareous shales were noticed fragments of fossil fishes, but 

 too obliterated for specific determination. They undoubtedly belong to 

 the Elko shales, and are therefore referred to the Green River Eocene. 

 They strike about north 20° east, and dip 30° to the east. This is the 

 westernmost of the Green River outcrops, exposures of Eocene lacustrine 

 deposits having never as yet been definitely recognized west of the Pinon 

 Range. 



To the east of this Eocene body, and penetrating it, lies a north and 

 south ridge, detached from any mountain-range, about 8 miles in length, 

 consisting of heavy beds of dark limestone, striking north 20° east, and 

 dipping to the east. 



It contains the following Coal-Measure fossils : 



Productas semireticulatus. 

 Froductus longispinus. 



It is evidently a part of the Wahsatch limestone, and directly to be 

 connected with the fragments of Wahsatch limestone of a corresponding 

 dip and strike, which lie to the east of the anticlinal north of Pinon Pass. 

 The strike and dip of this limited body of limestone, which overlies the 

 Ogden Quartzite, and is itself masked by overlying rhyolites, would, 

 if continued, bring the Devonian beds directly under the Green River 

 Eocene, at the west base of the limestone ridge. There can be little doubt, 

 in connection with the fossils, that this is really the upper part of the Wah- 

 satch limestone, and is the equivalent of the heavy beds of limestone which 

 overlie the Ogden Quartzite west of Raven's Nest Peak ; the rest of the 



^ Microscopical Petrography, p. 195. 



