GEOLOGICAL SURVEY OF THE TERRITORIES. 



109 



The streams that form the headwaters of the Gallatin Eiver have 



cat profoundly into the mountain- ^ 

 ranges, exposiog- their structure in » 

 the most beautiful manner. The | 

 first of the canons to which I will | 

 refer is SpringorKockCaiiou. This g 

 canon foims a most interesting sub- | 

 ject of study, and will answer ad- g 

 mirably as a type of the others. It -? 

 is a V-shaped chasm, cut through ? 

 the end of an anticlinal range by ^ 

 the stream. The trend of this range s: 

 is northwest and southeast. The |: 

 first thing that attracts our atten- § 

 tion after we are fairly inside the S" 

 canon is the occurrence, on the left- ° 

 hand side of the creek, of an arch S 

 that crosses the road, and, describ- ^ 

 ing a semicircle on the hill, again | 

 crosses the road at the upper end g: 

 of the canon. (Fig. 20.) The first i° 

 prominent bed we meet is a layer ^ 

 of coarse, gray calcareous sand- '^ 

 stone, containing fragments of fos- g 

 sils. Proceeding up the canon we |' 

 find the center of the arch is occu- o 

 pied by masses of Carboniferous s- 

 limestone, which tower far above B. 

 the creek, giving a most pictur- I" 

 esq,ue ai>pearance to the cailon. g 

 Still farther along we come to the f 

 other extremity of the arch and I 

 find the same layer that we saw at | 

 the opposite end. Following this " 

 layer at the western end of the h 

 canon, that nearest Fort Ellis, we h 

 find the dip at the bed of the creek |. 

 to be south 450 west; angle, 300-40°. ^ 

 Farther along we find it to be south g" 

 80° west, the angle renminiug about I' 

 the same. Still higher up "on the p 

 ridge it is north 50° west; angle, ^ 

 150-250 ; and when we reach the g: 

 highest point on the ridge it dips t 

 due north at an angle of about 25o. y 

 Taking this same layer again at the w 

 level of the creek, this time at the J; 

 eastern end of the canon, we find I 

 the dip to be in the same direction, | 

 although the angle is greater. As 'J 

 we go toward the south it ap- 1« 

 preaches more and more to the ver- «= 

 tical, until the dip becomes north- | 

 east and the range therefore be- ? 

 comes a true anticlinal. The read- | 

 lug just above the creek on the 



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 z 



northern side gives a dip of south 45© west; angle, 70°. As we follow 



