GA.M.-ETT.] TOPOGRAPHY THE MADISON DRAINAGE AREA. 485 



curved surface, roughly resembling a segment of a sphere. On the east 

 and south are almost sheer cliffs from base to summit. On the summit 

 is a little nipple, rising a couple of hundreds of feet above the main 

 mountain, the last remains of higher beds. 



The range ends abruptly in Mount Holmes, one of the finest and most 

 prominent mountains in the Park. I have named it after Mr. W. H. 

 Holmes, 'svho has been connected with the survey as geologist and artist 

 since 1872. Farther to the south the divide between the heads of 

 Gardiner's and Gibbon Eivers on the east and the Madison on the west 

 (for in this latitude we are beyond the head of the Gallatin) is borne 

 on a mere swell in the plateau. 



THE MADISON DRAINAGE AREA. 



Area within the Park, 730 square miles. The Madison is the middle 

 one of the three forks of the Missouri which join at Gallatin City. The 

 portion of the river within the limits of the Park is known more com- 

 monly as the Firehole. The stream heads just west of Shoshone Lake, 

 separated from it and the head of Bechler's Fork by relatively low 

 divides. At high water the stream has its source in a small pond, a 

 hundred yards or more across, known as Madison Lake. In the dry 

 season this pond ceases to exist, although a bit of marshy ground indi- 

 cates its site. The stream at first pursues a northeast course in a narrow 

 valley, then comes a bit of canon, followed by a like succession of open 

 valley and caiion. The valleys are narrow and marshy, and traveling 

 is not easy. In the second bit of caiion, about 8 miles from its head, 

 the stream turns to the northwest, and in 3 or 4 miles flows out into the 

 Upper Geyser Basin. So far the stream has received no large branches. 

 The principal branch in this portion of its course comes down a deep 

 caiiou from the east and enters it at the head of its bend. The stream, 

 however, has grown very rapidly, but it is mainly from springs along 

 the edges of the valley 



The Upper Geyser Basin is a valley of about a dozen square miles, 

 nearly flat as to surface, and surrounded by blufl", rocky walls on all 

 sides, except where the Madison (Firehole) and its branches enter and 

 find exit. A full description of this basin, with the others, will be found 

 in Br. A. C. Peale's report, so that it is unnecessary to enter into 

 further description. At the foot of this Basin the river receives two 

 large branches from the west, Little Firehole River and Iron Spring 

 Creek, which join one another just before entering the main stream. 



A few miles of a northerly course, in a narrow valley, between high 

 timbered hills, and the Firehole flows out into the Lower Geyser Basin, 

 a somewhat larger valley, containing about 20 square miles, and limited, 

 but not as closely or abruptly as the Upper Basin, by high hills. At 

 its head a small stream comes in from the east, while at its foot two 

 large streams join it from the west — Sentinel and Fairy Fall Creeks, 

 and a second stream from the east, known as the East Fork of the Fire- 

 hole. This is a large stream, heading in the Yellowstone divide, oppo- 

 site Alum Creek and other smaller streams. It has many branches, with 

 short, steep courses, which collect in a basin at the base of the divide, 

 whence the stream i^ursues a course nearly west, down a narrow valley 

 between high, steep walls. The country south of it and east of the Fire- 

 hole is high and undulating, with little drainage, and covered with a 

 dense growth of timber. 



The Firehole continues in a northwesterly course for 5 miles below 

 tlje moutli of East Fork, when it is joined by Gibbon River, a large 

 branch nearly equal in size, heading off to the northeast among the 

 densely timbered plateaus opposite the head of Gardiner's River. In 



