84 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



general form, but instead of being composed of calcareous material are 

 siliceous. The Te Tarata (described in Part III of this report) covers 

 an area of about 12 acres, and the head of the deposit is nearly 80 feet 

 in elevation above the level of the lake. The springs and formations 

 near Hierapolis, however, more nearly resemble our springs. (See de- 

 scription in Part III.) But even they are not so extensive. The forma- 

 tion, however, is calcareous, very like that of the Mammoth Hot Springs. 

 In various parts of the region west of the Kocky Mountains also are 

 old deposits from hot springs which, when active, must have closely re- 

 sembled the Gardiner's River Springs. 



CHAPTER II. 



SPRINGS OF THE YELLOWSTONE EIVER BELOW THE GRAND FALLS, 

 INCLUDING THE EAST FORK. 



In this chapter will be described three spring areas somewhat sepa- 

 rated from each other. 



The first area includes the springs of Junction Yalley and Tower 

 Creek, which are situated in rhyolitic rocks. 



The second area includes the almost extinct springs which are located 

 in Tertiary rocks. 



The third area is that just south and southeast of Mount Washburn, 

 and includes the Washburn Groups, the springs of the Grand Canon, 

 the Orange Creek Springs, and the Wayside Group. The two latter are 

 not indicated on the geological map of the Park. The Forest Group 

 might also have been described here, but it is just on the edge of lake 

 deposits of Hayden's Valley, and I have therefore put it in the follow- 

 ing chapter (III). 



JUNCTION VALLEY SPRINGS. 



In Junction Valley, the beautiful small valley in which the East Fork 

 joins the Yellowstone, there are several unimportant springs which were 

 not visited this year, as it was nightfall when we passed them, and we 

 did not deem them of sufficient importance to delay, especially as they 

 were examined in 1871 and 1872. The positions of the springs are indi- 

 cated on the geological map (Mr. Holmes's). The first spring noticed 

 is on the west side of the trail. It is small, and barely warm, giving a 

 deposit of sulphur. 



In the lower end of the canon of the Yellowstone that begins at Tower 

 Creek and extends to Baronette's Bridge there are numerous small sul- 

 phur springs. They are near the edge of the river in an inaccessible 

 place, and give off sulphuretted hydrogen in such quantity that it is 

 easily recognized on the upper edge of the canon 500 feet above the 

 springs. 



Most of the springs in this region, however, represent the last stages 

 of thermal activity, and are only referred to here for the sake of com- 

 pleteness. Sulphur appears to be the most abundant deposit; iron- 

 stains were also noted on the sides of the canon. 



TOWER CREEK SPRINGS. 



On the west side of the Yellowstone, between the mouth of Tower 

 Creek and Antelope Creek (formerly called Warm Spring Creek), there 



