.140 ABSABOKA DrVISION OF YELLOWSTONE EOREST EBSEKVE. 



the stands complete destruction has been the result. The region has always been 

 subject to widespread and destructive forest fires, as proved by the age of the timber. 



BIG TIMBER QUADRANGLE. 



LOCATION, EXTENT, AND CLASSIFICATION OF LANDS. 



The region embraced in the Big Timber quadrangle, Montana, is situated 

 between 46° 30' and 46° north latitude and between 109° 30' and 110° west longi- 

 tude, and contains an area of 634,283 acres. Forest, woodland, agricultural, and 

 grazing areas are represented within the quadrangle, the acreage of the different 

 classes of land being shown in subjoined table. 



Classifiaiion of lands in the Big Timber quadrangle, Montana. 



Acres. 



Forested *- : 27, 000 



Woodland '. 206,000 



Nontimbered 301, 283 



Total 534,283 



The nontimbered lands, excluding the areas of bare rock, differ but little in their 

 general features, except as regards their water supply and dependent irrigation 

 facilities. They are classified as follows: 



Classification of nontimbered lands in the Big Timber quadrangle, Montana. 



Acres. 

 Agricultural 34, 300 



Grazing , 253, 283 



Bare rocks : 13, 700 



Total 301,283 



TOPOGRAPHIC FEATURES. 



Excepting the southwest quarter, the quadrangle is a rolling plateau area cut by 

 many shallow, more or less rocky, and in some cases gorge-like, canyons. Broad 

 swells and low, rocky, irregular ridges separate the different ravines and canyons. 

 The lowest altitude is in the valley of the Yellowstone, which bisects the quadrangle 

 from west to east. The valley varies from 1 to 3 miles in width, and is made up of 

 two to three low terraces, bordered by low bluffs of sedimentary rocks, which present 

 sharp scarps to the river front and alternately approach and recede from the imme- 

 diate river except in the northeast quarter of the quadrangle, where they are close to 

 the stream for a distance of 18 miles and display a steep, solid front of rock 300 -to 

 400 feet in height. 



The southwest quarter of the quadrangle consists of mountain areas formed by 

 the terminations of northward-projecting spurs from the Granite Mountain district 



