CAMBRIAN CORDILLERAN SECTIONS — WALCOTT I9I 



BLACKSMITH FORK SECTION 



Locality. — Wasatch Mountains, between Ute and Logan Peaks, 

 in Blacksmith Fork Canyon, east side of Cache Valley, and 12 to 16 

 miles east of Hyrum, in northern Utah. 



This section is 230 miles northeast of the House Range section 

 and north of the greater effect of the pre-Cambrian Uinta Mountain 

 uplift and island. The character of the sediments derived from 

 the Uinta area is shown by the continuation of the arenaceous 

 deposits up to the middle of the Middle Cambrian (Acadian) time, 

 whereas in the House Range section the arenaceous deposits cease 

 before the Middle Cambrian fauna appears. It is not until after the 

 Belt Mountain and Kintla (of the 49th parallel) uplifts to the north 

 are passed that the order of sedimentation, as shown in the Mount 

 Bosworth section, is again of the type of that of the House Range 

 section. 



ORDOVICIAN 



Feet 

 I. Dark, bluish black and gray limestone. In the basal bed imme- 

 diately above the Cambrian a fine fauna occurs. The lime- 

 stone is of the same character as that of the Upper Cambrian 

 for 190 feet below and, except for the change in the fauna, 

 there is no break in the section. One of the characters 

 common to the Cambrian and the superjacent Ordovician is 

 the presence in most layers of flattened conci'etionary nodules 

 and stringers from a minute size up to 6 or 8 cm. or more 

 in diameter; the large ones rarely exceed 3 to 10 mm. in 

 thickness. 



Fauna: 



Eoorthis coloradoensis (Meek) [1870, p. 425]. 



Syntrophia nundina Walcott [1905, p. 292]. 



Orthoceras. 



Endoceras. 



Fragments of trilobites. 



UPPER CAMBRIAN 



ST. CHARLES FORMATION [Walcott, 1908a, p. 6] : 



I. Dark bluish gray and gray limestone in layers varying from i 

 to 20 inches in thickness. Many of the layers are almost 

 made up of flattened concretions varying from a minute size 

 to 6 or 8 cm 190 



Fauna (25 feet below the top) : 



Lingulella manticula (White) [1874, p. 9]. 

 Eoorthis coloradoensis (Meek) [1870, p. 425]. 

 Syntrophia nundina Walcott [1905, p. 292]. 

 Dicellocephains. 



