CHAPTER III. 



THE TfiTOIf, OR MIDDLE SECTION 



GENERAL TOPOGRAPHICAL FEATURES, DRAINAGE, ETC. 



The region referred to under the above designation assumes the 

 outline of a right-angle triangle, the base of which rests on the north- 

 ern boundary and the two sides defined by the great southern bend of 

 Snake River, its apex extended south nearly severing the district, of 

 which it includes almost a third of the explored area, or aj^proximately 

 2,000 square miles. Of this area i)erhaps one-third may j^ertain to the 

 great basin region lying to the northwest and to which properly belongs 

 the bay-like recess of Pierre's Basin, which latter separates the moun- 

 tainous portion into a clumsy \/ -shaped area, which forms the whole of 

 the eastern and two-thirds of the western side of the triangle. 



The local drainage of this section mainly flows out into the great plain 

 to the northwestward through Pierre's River, whose numerous affluents 

 collect the drainage of the larger area of the Teton Mountains, the two 

 principal branches rising at either extremity of the range above 40 miles 

 distant, the North Fork heading in the extreme northern portion, and 

 the sources of the main stream originating at the opposite or southern 

 end of the range, in the vicinity of Teton Pass. Moody Creek and two 

 or three smaller tributaries rise in the northern highlands of the Snake 

 River Range, the former gaining Henry's Fork, intlependently, midway 

 between the delta of Pierre's River and the confluence of the Snake. 

 The mountain border region sends down myriads of little streams, the 

 largest of which have a course seldom exceeding 10 miles, and which 

 drain directly into the Snake. While many regions may be as thoroughly 

 drained, few are so well supplied with noble rivers, rapid creeks, and 

 beautiful mountain brooks as this which we have at present under con- 

 sideration. 



THE TIPTON RANGE. 



The plains, which constitute a third or more of the northwestern por- 

 tion of this section, form i)art of the great basaltic-floored basin of Snake 

 River, which stretches along the northern border and far uj) Pierre's 

 Basin, its eastern margin resting on the western slope of the Teton 

 Range. This range, which holds a nearly meridional coiu'se, extending 

 from the northern boundary of the district a distance of about 40 miles 

 south, and ranging from 10 to 15 miles in east-west extent, is remark- 

 able for its regidar form, simplicity of geological structure, and the 

 grandeiu- of tlie concomitant topographic features. The longitudinal axis 

 of the range is crowded to the east, rising into a chain of Archaean 

 peaks Avhich culminates midway between the extremities of the range in 

 a cluster of lofty peaks dominated by Mount Hayden, Avhich attains an 

 actual altitude of 13,737 feet. The eastern front breaks suddenly down 

 in steep inclines to the level of Jackson's Basin, jnerced by profound 

 gorges which throw this aspect of the range into a series of gigantic 

 buttresses surmoimted by precipitous and embattled parapets. 



The . western side of the range descends much more gradually, and 



411 



