508 DESCEIPTIVE GEOLOGY. 



mouth of the cailon passes through quartzite. On the summit of Orford 

 Peak rests an isolated body of gray limestone from 150 to 200 feet in 

 thickness, thinning out to the northeast, all but this small fragment having 

 been eroded. Beneath this limestone occurs a thin bed of dark, steel-gray 

 quartzite, which, in turn, is underlaid by a somewhat coarse conglomerate 

 filled with flint nodules and pebbles, and resting directly upon the massive 

 quartzite. These beds strike north 28^ to 30° east, and dip at an angle of 

 30° to the northwest. 



Large numbers of fossils were collected from this limestone, and the 

 following species, among the Brachiopoda, have been recognized: 



Ortlis carhonaria. 

 Productus semireticulatus 

 Produdus pundatus. 

 Produdus Nebrascensis. 

 Produdus longispinus. 

 Spirifer cmneratus. 

 AtJiyris subtilita. 

 AthyrisBoissyL 



Associated with them are corals belonging to the genus Campophyllum. 

 A characteristic feature of the Carboniferous limestone of the northern end 

 of the range are the interstratified beds carrying nodular concretions and 

 fragments of flint, and black bands of siliceous cherty rock, with an exceed- 

 ingly fine-grained texture, and a rough irregular fracture. They usually 

 are marked by narrow bands of chalcedony, and give, when treated with 

 acid, a slight reaction for carbonate of lime. 



Directly north of Holland Pass occurs a body of limestone, forming 

 the higher summits of the range, which has been but little studied, and, 

 although its relation to the great quartzite body has not been observed, it is 

 provisionally regarded as underlying it, and has therefore been referred to the 

 Lower Coal-Measure series of the Wahsatch limestone. A recorded strike 

 on the summit gave north 30° west, with an easterly dip. South of Holland 

 Pass, the range consists of nearly parallel ridges trending a few degrees west 

 of north and east of south, that is, obliquely to the main trend of the uplift. 



