A FRACTURE VALLEY SYSTEM I 01 



Peak to Mount Delano rise abruptly on the east side of the val- 

 ley, while on the west there are the long sloping spurs of volcanic 

 lavas overlying sedimentary strata in the northern part of the 

 Gallatin Range. The location of this fault was not discovered 

 in the field, as it is undoubtedly obscured by the valley deposits. 

 It dies out abruptly before reaching the Lower Canyon, near 

 Livingston, and is probably most profound north of the cross 

 fault at Mill Creek. 



This northeast direction is the same as that of two pronounced 

 faults in the southwest corner of the quadrangle that enter it 

 from the Yellowstone National Park. One lies in the drainage 

 channel of Cinnabar Creek ; the other is in the valley of Reese 

 Creek. It is probable that a third fault parallel to these occurs 

 in the valley of Gardiner River west of Mount Everts, but it has 

 not been definitely located, These faults terminate in the great 

 northwest fault in Yellowstone Valley south of Sheep Mountain. 



The throw of the Cinnabar Creek fault is to the west, but the 

 extent of the displacement is not determinable. It has been 

 traced for a distance of eighteen miles. The Reese Creek fault 

 is clearly recognizable east of Electric Peak, where the throw is 

 to the east and the displacement more than 6,000 feet. It con- 

 tinues southward as a scarp fault along the east flank of the 

 Gallatin Mountains in the Yellowstone Park. It is known for 

 twenty miles, and disappears under lava. The throw of the fault 

 west of Mount Everts is to the west. 



A minor fault parallel to those just described occurs in the 

 gneiss east of, and parallel to the channel of Hell Roaring Creek. 

 Several northeast-southwest faults of slight extent have been 

 noted north of the great body of crystalline schists. One is a 

 short spur connected with the fault in the valley of the East 

 Boulder River. Two are connected with the northwest-southeast 

 faults southeast of Livingston, and another is south of Mount 

 Ellis in the western part of the quadrangle. In each of these 

 cases it is interesting to observe that there are conjugate faults at 

 nearly right angles. 



In the direction of the northeast-southwest fractures, besides 

 the Yellowstone Valley and Cinnabar and Reese Creeks, which 



