GEOGRAPHY. ] ] 
and for 190G. Additional material obtained by Brooks and ( overt 
in 1907 has been added. The description of the Rampart region is 
taken largely from a Survey bulletin," and as that report is now out 
of print the account of the placers, by Frank L. Hess, is here re- 
printed. This account is supplemented by data obtained by Mr. 
Brooks in the Rampart region. 
GEOGRAPHY. 
The area under consideration in the two quadrangles, about 1 1,000 
square miles, is bounded by the 146th meridian and Yukon and 
Tanana rivers and has about the shape of an equilateral triangle^ 
whose eastern side is the 146th meridian and whose western ansrle is 
at the confluence of the two rivers. The area is made up of ridges 
and valleys bordered on the north by a part of the Yukon Flats, 
deeply embayed on the south by the Tolovana Flats, and terminated 
on the west by the low area between the two rivers. 
The dominant type of country is one of ridges more or less uniform 
in height, with altitudes of 2,000 to 3.000 feet, separated by valleys of 
equally uniform depth, but certain areas, like the White Mountains 
and, 50 miles farther west, the group of hills near Rampart, attain 
altitudes of 4,000 to 5,000 feet or more, and these areas are accen- 
tuated on the maps by the greater number and more closely crowded 
character of the contour lines that represent their slopes. The coun- 
try between these two main features comprises many ridges, which 
are in general higher toward the northern part of the area and break 
off abruptly to the Yukon Flats or Yukon River. The southern limit 
of the hill country is less abrupt, and the ridges merge more gradu- 
ally into the valleys of the Tanana and its tributaries. The valley- 
exhibit much variety; some of them are deep, steep walled, and nar- 
row, with but little floor; others have well-developed floors and 
gentler slopes, and others become extensive flats. Some of them are 
complexly interwoven and follow most tortuous courses before leav- 
ing the hills and joining the main lines of drainage. The important 
tributaries of the Yukon are Beaver, Hess, and Minook creeks; those 
tributary to the Tanana are the Salcha, Chena, and Tolovana rivers 
and Baker Creek. 
The Yukon Flats extend far northward from the base of the ridges 
to the plateau country fronting the Rocky Mountains. The sparsely 
timbered surface is somewhat uneven and broken where minor ridges 
run out into it from the base of the hills. Tt is dotted with a lew 
small lakes, and the small streams that furrow the northern -lope- of 
the hills cross it in rather ill-defined valleys. Distant shimmering 
"Prindle, L. M.. and Hess, F. L., The Rampart gold placer region, Alaska: null. D. s 
Geol. Survey No. 280, L906. 
