TTMPANOGOS PEAK. 349 



Above the narrow main ridge, the canon opens out suddenly into Provo 

 Valley, in which the ridges and hills are covered with soil and debris, and 

 overgrown with grass and timber. Only isolated and detached outcrops of 

 the underlying rocks, which were doubtless once covered by Tertiary, and 

 perhaps also by Cretaceous beds, can now be found. In the hills immediately 

 above the canon-narrows, the presence of the Weber Quartzites is indicated 

 by outcrops of light-colored sandstones and quartzites, while in the valley 

 above, near where it opens out into the main Provo Valley, were found, to 

 the north of the river, limestone strata containing rather poor specimens of 

 BakevelKa, but which were sufficient, in connection with the overlying red 

 sandstone, to determine the horizon as the Permo-Carboniferous, and the 

 intermediate group of Upper Coal-Measure limestones has hence been 

 colored upon the map inferentially. 



The limestone strata rise gently both to the north and to the south 

 from Provo Canon. In the Timpanogos Ridge, this rise continues to the 

 granite body of Lone Peak. Timpanogos Peak itself is a narrow ridge, 

 only a few feet wide at its summit, falling off at a very steejD angle for 

 3,000 to 5,000 feet on the east and west, composed of approximately hori- 

 zontal strata of the Wahsatch limestone. A high spur extends from its 

 highest point to the eastward, enclosing an ampitheatre-like basin, sheltered 

 on the west and south by sheer walls over 3,000 feet in height, in which a 

 large body of ice and snow remains probably throughout the year. The 

 beds which form the upper portion of this ridge belong to what was first 

 called the intercalated series, and consist of alternate layers of thin lime- 

 stones and limestone-shales, with light-colored siliceous slates and quartzite. 

 They form an easily recognizable horizon, indicating the upper portion 

 of the Wahsatch limestone, and generally contain many well-preserved 

 Spirifers, whose shells have been replaced by white calcite, which forms a 

 strong contrast with the blue or gray matrix in which they are imbedded. 



Among the fossils brought in from this horizon on Timpanogos Peak 



were: 



Spirifer cameratus. 



Atliyris suhtilita. 

 In the lower portion of the ridge, the limestones are generally of darker 



