240 F. C. SCHRADER GEOLOGICAL SECTION LN NORTHERN ALASKA 



Structure. — The Totsen series, like the other rocks composing the range, 

 trends approximately east and west, and though as a whole the series 

 has been intensely folded, the dip in general is monoclinal, being south- 

 ward at an angle of 60 degrees. The major and minor jointings of the 

 range are pronounced. Cleavage was noted at several localities. 



Age. — Though the Skajit formation and the Totsen series have un- 

 doubtedly been folded and crushed together, judging from the apparent 

 higher degree of metamorphism in the Totsen series we should infer that 

 it may prove to be the older, notwithstanding, it seems to overlie the 

 southern edge of the Skajit formation. It is provisionally referred to the 

 Upper Silurian with the Skajit series. 



STUVER SERIES (PRE-DEVONIAN) 



Character and occurrence. — The Stuver series is the oldest group of rocks 

 exposed in the northern axis of the Endicott range, of which they form 

 the core. This is on the east and west line of the most pronounced and 

 geologically most recent crustal disturbance. The uplift, which seems 

 to have been going on since middle or late Paleozoic time, has taken the 

 form of a broad anticline whose longer limb extends to the southward, 

 while the shorter forms in part the north front of the range. Elevation 

 was accompanied by faulting; the movement or thrust came from the 

 south, and along the axis of the anticline has produced an over thrust 

 fold or fan structure. On the north, faulting has resulted in the break- 

 ing of the strata and the formation of a fault scarp in the north limb of 

 the anticline, between the north edge of the Stuver series and the Lis- 

 burne formation. This was farther accompanied and followed by fault- 

 ing and erosion, which broke up the immediate region into several great 

 fault blocks, and finally brought the Stuver series into view along the 

 bight of the fold. From the north edge of the range pronounced faulting 

 extends southward into the range for a distance of 15 or 20 miles. The 

 Stuver series consists primarily of hard flinty conglomerate and quartzite, 

 with some slate and shale. 



Structure. — The exposure is limited to a narrow belt about 5 miles 

 in width, trending northward for an unknown distance from the Anak- 

 toovuk valley between the faulted and eroded edges of the Lisburne 

 formation on either side. On the south, by uplift and faulting, it has 

 probably been brought into contact with the lower Carboniferous of the 

 Fickett series. Both here and at the north edge of the series, the fault- 

 ing, as shown in the section, seems to be normal, but in the Stuver series 

 the major jointing trends about east and west and the minor nearly 

 north and south. The series is cut by a well marked cleavage, dipping 

 northwest at an angle of 45 degrees. The undisturbed relation of the 

 Stuver series to the Lisburne formation is apparently conformable. If 

 any unconformity exists, it must be very slight. 



