370 DESCEIPTIVE GEOLOGY. 



shales, which can be very distinctly seen both below and above the beach- 

 line. Here were found : 



Aviculopecten Weberensis. 

 Aviculopecten curtocardinalis. 

 Aviculopecten McCoyi. 

 Aviculopecten parvula. 

 SedgwicMa concava. 

 Eumicrotis Hawni. 

 Myalina Permiana. 

 Myalina aviculoides. 



At the month of Emigration Canon are seen the dark-red sandstones 

 and overlying pinkish-striped sandstones of the Triassic, which are capped 

 by the drab limestones of the Jurassic, all dipping north, and forming the 

 outlying northern member of the great anticlinal fold, whose southern side 

 is seen, partly buried beneath the overlying Cretaceous or Tertiary, in 

 Provo Valley. The thickness of the Triassic at this point cannot be readily 

 estimated, but apparently does not vary much from that found where the 

 section is more regular, as in Weber Canon, viz, 800 to 1,000 feet. 



In this foot-hill section, it is evident that the strata have been sub- 

 jected to severe compression, and, besides the anticlinal between Parley's 

 and Emigration Canons, there may be other minor folds or faults, which 

 have escaped observation, which, from palaeontological evidence, are prob- 

 ably in the Upper Coal-Measures, since here the Permo- Carboniferous forms 

 are found to have a much wider vertical range than in other sections, where 

 they are generally confined to the upper 500 to 700 feet of the series. The 

 dividing line between the Permo-Carboniferous and Upper Coal-Measures, 

 as drawn here, therefore, is one which cannot be distinctly defined in the 

 field, since in lithological character the distinction of mud beds and lime- 

 stones, which serve as a general division, cannot be followed, and the fauna 

 is very much mixed through all, except the very lowest members of the 

 latter. The theoretical thickness of beds, calculated from width of outcrop 

 and dip, between the top of the Cambrian and that of the Triassic, does not, 

 however, exceed very much that obtained from the combined average thick- 



