EARLY CAMBRIAN STRATIGRAPHY. 
Ill 
if present at all, is succeeded by siliceous shales and appears to 
be of Lower Cambrian age in all of the examined sections south 
and southwest of Ogden canyon, Utah, and north and east of 
the Highland range, Nevada. These include the Stansbury 
Range (Muskrat Spring), Oquirrh Range, Simpson Range, Beaver 
River Range (Cricket Spring), and House Range sections. The 
basal quartzite series is not exposed in the other sections measured 
in this area. In the Highland range 1 the basal quartzite series 
is separated from the Olenellus gilberti zone of the Pioche forma- 
tion by 35 feet of limestone. 
In the Grand Canyon, Big Cottonwood Canyon, Phillipsburg, 
Mount Bosworth, and Mount Robson sections, variations in 
the degree of metamorphism between the Cambrian and Pre- 
Cambrian are so slight as to make this criterion of little value. 
At Elko only is there a pronounced difference. 
In the Grand Canyon, Big Cottonwood Canyon, and Phillips- 
burg sections the unconformity between the Cambrian and Pre- 
Cambrian involves angular discordance; in the other sections 
unconformity can be proven only by overlap, basal conglom- 
erates, etc. 
The Cambrian and Pre-Cambrian systems both appear to be 
represented in the Grand Canyon, Big Cottonwood Canyon, 
Dearborn River, Phillipsburg, Elko, Mount Bosworth (?), and 
Mount Robson (?) sections; in Ogden canyon and in the Big Belt 
and Little Belt mountains the Cambrian rests on the Archaean. 
The Pre-Cambrian does not appear to be represented in the 
Highland Range, Pioche, House Range, Wasatch Canyon, 
Blacksmith Fork, Mill Canyon, and Malade sections. 
The Lower Cambrian is not represented by fossil evidence 
in the Blacksmith Fork, Malade, Wasatch Canyon, Mill Canyon, 
Big Belt and Little Belt Mountains, Dearborn River, Phillips- 
burg (?), and Elko (?) sections. 
The relations of the Lower Cambrian to the over- and under- 
lying strata do not appear to have been observed in the Waucoba 
Springs or Silver Peak sections. 
1 Walcott: Bull. XJ. S. Geol Survey, No. 30, 1886, p. 33. 
