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No. G.— A GEOLOGICAL EXCURSION IN THE GRAND 
CANON DISTRICT. 
BY DOUGLAS WILSON JOHXSOX. 
Introductiox. 
The salient'features of the Grand Caiion district have been made 
famiUar by tlie classic works of Powell and Dutton, and by the more 
detailed local studies of later observers. An ap])roximately parallel 
series of north-south faults and folds divides the district into a number 
of subordinate |)lateaus, as indicated on the accompanying sketch 
map (fig. A). ' 
North of the Colorado River the several jilateau blocks are called 
from east to west, the Marble Caiion Platform, the Kaibab Plateau, 
the Kanab Plateau, the Uinkaret Plateau, and the Shivwits Plateau. 
South of the river the displacements are less prominent, and have not 
been carefully traced. Hence a single name, the San Francisco 
Plateau, is given to this jiortion of the district. 
The name Colorado Plateau has often been aj^plied to this southern 
area, but such usage leads to confusion, inasmuch as the whole province 
is known as the Colorado Plateau province. It seems better to follow 
Powell ('75, pp. 1S6, 195; '95, p. 94) in his employment of the name 
San Francisco for this subdivision of the province. Gilbert ('75, p. 
47) formally applies the name Colorado Plateau to this area but 
later speaks of it repeatedly as the San Francisco Plateau (Gilbert, 
'75, pp. 109, 116, 542). Robinson ('07, ]). 109) has recently defined 
the limits of this particular subdivision of the ]>lateau province, and 
employed the name San Francisco to designate it. The name is appro- 
priate, for the district is dominated by the San Francisco INIountain 
group, of which San Francisco Peak is the highest point, while a large 
part of the area is included in the San Francisco Forest Reserve. The 
name Coconino Plateau is generally restricted to the higher portion of 
the San Francisco Plateau lying south of the Kaibab. 
The following notes were made during the summer of 1906 in the 
course of a wagon trip from Prescott, Arizona, to Salt Lake City, 
Utah, and are offered as a brief contribution to Our knowledge of the 
physiographic features of the Grand Canon district. 
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