BEEEY CEEEK. 153 



covered by Flathead quartzites and Paleozoic limestones, dipping at low 

 angles toward the northeast. 



East of Forellen Peak, on the crest of the mountain, the gneiss is 

 overlain by indurated sandstones having a strike N. 55° W. and a dip of 

 20° NE. Lower down on the northern side of the ridge light-gray mottled 

 limestones are exposed in a nearly vertical position. They are associated 

 with green micaceous shales and a thin layer of ferruginous sandstone. 

 Although no fossils were found, there is little doubt that the beds belong- 

 to the basal portion of the Cambrian. A short distance farther east the 

 limestones strike N. 45° W., and clip 30° E. 



The crest of the east ridge of Forellen Peak and the eastern slope of 

 the mountain are covered by a thin sheet of lithoidal rhyolite, like that 

 forming the plateau north of Berry Creek, of which it is unquestionably 

 an extension, being connected with- it across the bottom of the valley. 

 The eastern end of the mountain is cut off by the canyon through which 

 Berry. Creek flows to join the Owl Creek drainage. 



East of the gneiss the sequence of sedimentary beds is quite the 

 same as that observed in the Survey Peak section, to be described (p. 160). 

 The relations of the beds, however, are partially obscured by the sheet of 

 rhyolite just mentioned. 



Berry Creek. — In the canyon of Berry Creek, just above its junction with 

 Owl Creek, the sedimentary rocks are well exposed, and a section was made 

 which shows the relative thicknesses of the Cambrian rocks. 



Section of sedimentary rods in Berry Creek Canyon. 



Nurn- Feet, 



ber. 



'22 Limestone, crackled, gray, crystalline, dense 25 



21 Limestone, granular, saccharoidal, buff, weathering -white 75 



20 Limestone, magnesian, gray with red layers, also rnagnesian, with fossils .. 50 



19 Limestone, gray, dense 10 



18 Limestone, gray, containing patches of red magnesian rock 300 



17 Limestone, gray, containing Carboniferous fossils 2, 000 



fl6 Limestone, brown, weathering steely gray, with fetid odor and resembling 



„ ,, , Devonian; beds arenaceous. 



Three Forks. < 



1 15 Limestone, thinly bedded; mottling produced by irregular bands of cream- 



l colored material. 



f 14 Limestone, dark gray ; thinly bedded, few feot - ] 



Jefferson J 13 Limestone, forming great ledge, rough, guttered, and pitted surface; no ) 150 



I fossils, except at top - J 



| 12 Limestone, gray with sandy patches - 100 



Gallatin { 11 Shales, gray and red 25 



I 10 Limestone, forming heavy ledge; brown gray 50 



Madison • 



