242 F. C. SCHRADER GEOLOGICAL SECTION IN NORTHERN ALASKA 



Fossils were also found in place, but these are too highly altered and 

 crushed for identification. 



FICKETT SERIES {LOWER CARBONIFEROUS) 



Character and occurrence. — The Fickett series comprises rocks of very 

 diverse character, ranging from chloritic schists or phyllites on the south, 

 through limestone, slate and sandstone, quartzite, and grit, to hard con- 

 glomerate on the north. As shown in the section, figure 1, the series, 

 roughly speaking, lies essentially in the broad trough between the two 

 axes of the range already described. This trough was probably occu- 

 pied by a shallow arm of the sea in late Paleozoic time, when the axis 

 on the north and the south stood above sealevel, and from which 

 sediments of the Fickett series have probably been in part derived. The 

 series has a width or north and south extent of about 50 miles. On the 

 south its edges rest unconformably on the Skajit formation of the 

 southern axis, as shown in the geological section, while on the north, 

 owing to the faulting, as noted at the head of the John and Anaktoovuk 

 rivers, its relations to the older rocks of the northern axis are not defi- 

 nitely revealed. It seems, however, to meet the Stuver series and Lis- 

 burne formation by fault contact, as has been indicated in the section. 

 To the north of this contact, so far as observed in the region of the 

 Anaktoovuk, all trace of this series in place, though it must have been 

 of considerable thickness, seems to have been removed by deformation 

 and erosion. To the westward, however, beyond the limits of the fault- 

 block system of the Devonian, at about 20 miles from the Anaktoovuk, 

 the Fickett series, as already noted, seems to overlie the Lisburne for- 

 mation and possibly extends beneath the Mesozoic at the north base of 

 the range. 



Structure. — The Fickett series, like the other Paleozoics of the range, 

 has been subjected to faulting and folding incident to the mountain- 

 building forces. The folding in some localities has been intense, as is 

 shown by closely appressed anticlinal folds, and puckering in the schist. 

 The structure, however, broadly speaking, is essentially monoclinal, 

 with strike and trend east and west and the dip south at an angle of 

 about 45 degrees, pointing strongly to a later and also to a greater ele- 

 vation along the northern axis than along the southern. The major 

 structure of the range is exhibited throughout the region covered by the 

 Fickett series. There are many faults whose planes are usually slicken- 

 sided and dip 70 to 80 degrees northwest. The minor jointing is also 

 present. The schists, and notably the phyllites, often exhibit excellent 

 cleavage, with medium north to northwest dips. 



