102 
MUSEUM BULLETIN NO. 2. 
welder 1 discusses the stratigraphy and structure in the Ogden 
Canyon region, correlating the shales immediately above the 
quartzite with the “Middle Cambrian [portion of the] Pioche.” 
The Langston limestone 2 is not present in the measured section, 
and while Olenellus was not secured from the layers immediately 
above the quartzite the succession appears to correspond more 
closely with that in the Big Cottonwood Canyon section less 
than 50 miles to the south than in the Bear River range to the 
northeast. 
Utah, Wasatch Mountains, Wasatch Canyon. — At the mouth 
of the first small canyon south of Wasatch canyon, 5 miles 
north of Brigham, Utah, the Spence shale is well developed and 
the succession is in every way comparable with that in the Bear 
River range (Mill canyon) to the northeast. 
Utah, Blacksmith Fork. — The basal quartzite series has an 
exposed thickness of 1,000 or more feet without observed uncon- 
formity, and grades upward into a series of massive limestones 
to which the name Langston has been applied. 2 The line between 
the Langston and the underlying Brigham is here drawn 500 
feet down in this gradational series, while at Malade and on 
Mill creek in the Bear River range, Idaho, localities within 
45 miles of the section in Blacksmith Fork, the Langston is 
very thin, sharply set off from the underlying quartzite, and 
crowded with fossils referable to the Middle Cambrian. In 
the Blacksmith Fork section no fossils were found in the Brfgham 
quartzite, but that formation, in the Mill Canyon section, has 
yielded fossils upon whose basis the Brigham quartzite has been 
referred, at least in part, to the Middle Cambrian. 3 
Idaho, Bear River Range, Mill Canyo?i Section. — The sedimen- 
tation in the Mill Canyon section of the Bear River range is 
closely comparable with that at Blacksmith Fork in the southern 
portion of the same range, see above. The Middle Cam- 
brian Brigham quartzite is clearly to be distinguished from the 
overlying Langston limestone, however, and the latter formation 
is here only 25 or more feet thick and abundantly fossiliferous. 
As in the Blacksmith Fork section it is conformably overlain 
1 Bull. Geol. Soc. America, vol. 21, 1910, pp. 526 and 534-539. 
2 Walcott: Smithsonian Misc. Coll., vol 53, No. 5, 1908, p. 198. 
3 Mon. U. S. Geo!. Survey, vol. LI, 1912, p. 153. 
