410 WILBUR C. KNIGHT 
discuss the validity of the term ‘‘Triassic’’ as applied to the 
Red Beds at the close of the chapter, but I have failed to find 
his reference. 
A portion of the Red Beds of the Laramie Plains occupies a 
belt of varying width along the western base of the Laramie 
Mountains. North of Laramie for a distance of forty miles the 
width varies from three to four miles, and the surface is gently 
rolling to within a short distance of the range, where there are 
now and then low hogbacks that have been cut with transverse 
gulches. South from Laramie the width gradually increases, 
and at Red Buttes is about six miles, and the eastern portion is 
marked with a great many eroded buttes which rise from 15 to 
50 feet above the surface. Almost due south from Red Buttes 
there is a long, narrow spur of Archean rocks known as Boulder 
ridge, projecting into the valley country, causing the Red Beds 
to narrow down to about three miles. North and east of the 
Archean exposure there is a tongue-like mass of Red Beds 
extending into a depression in the Archean to the south of Tie 
Siding, and, if the width of the formation east and west is esti- 
mated from this place, it will be over twelve miles. Southward 
from Boulder Ridge the Red Beds widen rapidly toward the 
Colorado line, and near that place have an east and west expan- 
sion of about eighteen miles. In Colorado they form a narrow, 
V-shaped mass that occupies the angle at the intersection of the 
Laramie and Medicine Bow Mountains; but are nearly covered 
with Jurassic and Dakota formations. 
Generally speaking, the topography of the Red Beds on the 
Laramie Plains is quite level or gently rolling. Occasionally 
the hogbacks are found near the ranges, and in three localities 
the surface is characterized by numerous buttes that have been 
worn into grotesque figures by wind erosion. These localities 
are Red Buttes, at the termination of Boulder Ridge and Sand 
Creek. Inthe latter place the wind-sculptured rocks are scat- 
tered along the valley for a distance of six miles, and present 
some of the most remarkable examples of wind erosion known 
in the state. The general forms are irregular domes of cross- 
