330 GEOLOGICAL EXCURSION TO THE ROCKY MOUNTAINS. 



character of the main range in this vicinity. The Mill Crock faults 

 disappear 9 miles cast of Mount Cowen, from which point the anticlinal 

 structure extends eastward. 



A cross section of the region from near the mouth of Mission Creek 

 on the Yellowstone River, 9 miles below Livingston, through Living- 

 ston Teak and Mount Cowen to Mill Creek (Fig. 14-A), will aid in the 

 understanding of the geological structure of this part of the region. It 

 exhibits the Paleozoic strata dipping steeply north and passing under 

 less highly inclined Mesozoic beds that form the broad valley of the 

 Yellowstone below Livingston. A slight fault crossing the peak south 

 of Livingston Peak has thrown down the sedimentary strata against the. 

 crystalline schists for a short distance. It shows the great body of 

 schist and granite forming the mountains along the east side of Yellow- 

 stone Valley to Mount Cowen and the faults at its southern base. 



S 3 /// 



a.Ycllowstone R. at Mission cr t> Livingston Peak c Mt. Cowen al Mill creek 





c. ML Cowen d. ~ Mill crecA c Emigrant Peak' f Yellowstone R at \hnkccJim. 



Yellowstone R. above Mdl cr e Emigrant Pk. s. Sheep Mt y. Yellowstone R.al Gardiner 



.<:.- 



* , 





Mesozoic. Pa/eozo/c. /Jrc/iaean: Agglomerates, /ntrusfues. 

 Fia. 14.— Snowy range sections. 



The valley of Mill Creek opens a vista into the region of volcanic 

 tuft's and breccia, mountains of which, 20 miles distant, may be seen 

 from the railroad just north of Chicory station. The peaks a short dis- 

 tance back from the mouth of this valley consist of igneous rock that 

 was intruded within sedimentary rocks and which undoubtedly rose 

 along the fault plane at the base of Mount Cowen. Similar intrusive 

 rock forms the high peak, Chico Mountain, between Mill Creek and 

 Emigrant Gulch, the deep valley immediately north of Emigrant Peak 



