Page:Walcott Cambrian Geology and Paleontology I.djvu/22

The following table gives a summary of the new formations defined, together with their thicknesses in each of the sections:

	Thickness (in feet).
	Blacksmith Fork.	West of Liberty.
Upper Cambrian:
St. Charles formation	1,225	1,197
Middle Cambrian:
Nounan formation	1,041	0,814
Bloomington formation	1,320	1,162
Blacksmith formation	0,570	0,023
Ute formation	0,759	0,731
Spence shale	0,030	0,030
Langston formation	0,107	0,030
Brigham formation	+1,250+	+1,000+
	6,662	4,997

St. Charles Formation

Type Locality.—Bear River Range, west of the town of St. Charles, in the Bear Lake Valley, Bear Lake County, Idaho. The most accessible locality is in Blacksmith Fork Canyon, east of Hyrum, Cache County, Utah.

Derivation.—From the town of St. Charles, near the typical locality. The stream flowing through St. Charles passes over the formation.

Character.—Bluish gray to gray, arenaceous limestones, with some cherty and concretionary layers, passing at the base into thin-bedded gray to brown sandstones.

Thickness.—In Blacksmith Fork Canyon, 1,225 feet; in the section west of Liberty, 1,197 feet.

Organic Remains.—Upper Cambrian, passing at the summit into Ordovician.

Nounan Formation

Type Locality.—Bear River Range, east slope of Soda Peak, west of the town of Nounan, in the Bear Lake Valley, Bear Lake County, Idaho. The most accessible locality is in Blacksmith Fork Canyon, east of Hyrum, Cache County, Utah.

Derivation.—From the town of Nounan, near the typical locality, Nounan Creek Canyon cuts through the formation.

Character.—Limestones. Light gray to dark lead-colored, arenaceous limestones.