112 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Tliioltness 



ill feet. 



14. Compact qiiartzito 4 



15. Couglonicrato 2 



IG. Yellow limestone 3 



17. Cberty limestone.. 15' 



18. Qnartzite 5 



lU. Limestone 20 



20. Calcareons sandstone 4 



21. Limestone 4 



22. Sandstone 15 



23. Quartzito 15 



24. Yellow calcareous sandstone 5 



25. Red sandstone 5 



26. Pnri)lo and greenish sandstone 2 



27. Spotted purple sandstone 4 



28. Brick-red sandstone 4 



21). Purple sandstone 3 



30. Greenisli-whitc qnartzite 2 



3L Purple sandstone 5 



32. Arenaceous limestone 



33. Limestone ' 



Outside of tlie qnartzite bed, with whicli I have beaded tlie above sec- 

 tion, there is a succession of beds of hard quartzites and conglomerates 

 followed by soft sandstones of steel-gray colors. Just below these sand- 

 stones, which are Cretateous, there is a layer of hard, green shale con- 

 taining fossils. Outside of them there occurs a bed of limestone. All 

 these beds curve around the Spring- Caiion layers, to w^hich they seem 

 to be conformable. Above the Cretaceous beds there is an immense 

 thichness of brown and dark-gray Tertiarj' sandstones, (Eocene,) contain- 

 ing beds of coal. They also follow the curve of the Cretaceous bcVls and 

 are seemingly conformable to them. Thej^ extend for four or five miles. 



About five miles north of Spring Caiion there is a range, the Bridger 

 Eange, the trend of whicli is north and south. I shall here refer only 

 to the southern end and western side of this range, reserving any 

 further consideration of it to a subsequent chapter. . Near the south- 

 ern end of the range there is quite a high jDeak known as Bridger's 

 Peak, which is 0,000 feet above the sea. The crest of the range is made 

 up of Carboniferous limestone, dipi:>ing southeast, containing Hemi- 

 pronites crcncstria, Produeius longispinus. Then follows a succession 

 of beds as we found them in Spring Canon. Following these, and still 

 dipping southeast, are the Cretaceous beds that we noticed outside of 

 Spring Canon. In a layer of hard, green shales I found Gri/pJuca, Avi- 

 cula, Pinna, Inoceramiis, Turritella, Cmssatcllaj &c., proving their un- 

 doubted Cretaceous age. Next we find the Tertiary sandstones, which 

 are unconformable to the Bridger layers. There is therefore between 

 Spring Canon and the Bridger Range a synclinal valley the floor of which 

 is Cretaceous, filled in with the Tertiary sandstones, dipping northwest, 

 north, and northeast at an average angle of 40°. Many of these sand- 

 stones are calcareous and contain veins of calcite. The thickness of these 

 beds must exceed 1,000 feet, and from the specimens of fossil-plants 

 found in them they are for the most part Eocene. Some of the upper 

 layers may be of JMiocene age. 



Opposite Fort Ellis, between our camp and Bridger Peak, there are 

 bluffs composed of Pliocene sandstones, marls, and conglomerates. The 

 strata are for the most part horizontal, althougli inclining sometimes at 

 a very small angle, which is never more than 5^. The height of these 

 bluff's above the level of the creek is 175 feet. They are the remnants 

 of Pliocene forauitions that once spread over the entire valley of the 

 Gallatin, and formed the bottom of a vast lake that spread over what 



