SURVEY PEAK. 159 



guttered surface, that has just been noted. The beds have a general strike 

 N. 35° W., and dip 80° SW. Upon the gneiss, directly east of the fault, 

 there is Flathead quartzite, dipping at a low angle toward the northwest. 

 The fissile Cambrian formations have been completely displaced at this point. 



The displacement noted on Forellen Peak probably diminishes north- 

 ward and may fade out east of Survey Peak, the steeply dipping- strata 

 continuing through this mountain into the hills north of it. Here the light- 

 gray and brown striped limestones of the Madison formation, which form 

 the main mass of Survey Peak, strike N. 25° W. and dip 70° SW. At the 

 eastern base of the mountain they have the same strike, but a lower dip, 

 about 25° SW. 



survey Peak. — On the slopes southeast of Survey Peak the gneiss is well 

 exposed, immediately overlain by the rusty Flathead quartzite with strike 

 N. 70° W. and dip 15° N. Above this ledge no exposures are seen for 50 

 feet, when limestones outcrop, the ledges being conformable in dip and 

 strike to the quartzites below. These limestones are dark gray, mottled 

 with buff spots of sandy material, and resemble the limestones occurring 

 in the Flathead shales. Above these beds the slopes show poorly exposed 

 limestones, eroded by glacial action into well-marked benches. Six hundred 

 feet, above the gneiss the beds consist of chocolate-colored cherty lime- 

 stones, alternating with gray crystalline limestones containing traces of 

 fossils and much cut up by veins and patches of calcite. On the east slope 

 of the mountain the beds are well exposed, forming rough, bare ridges 

 devoid of soil or timber. 



The best section of the Paleozoic rocks is to be found north of the 

 creek, in the slopes which fall away from the eastern flanks of Survey Peak. 

 Here we have a continuous series of beds from the Archean to the red 

 shales and clays of the Teton formation. The section given on the next 

 page was measured at this point. 



