COKWIN AND ANAKTOOVUK SERIES 245 



near Wainright inlet, the Beaufort series is provisionally assigned to the 

 Jura-Cretaceous. 



The forms from near Wainright inlet are as follows : 



Nageiopsis longifolia Font. Older Potomac of Virginia (Lower Cretaceous). 

 Podozamites distantinervis Font. Older Potomac of Virginia (Lower Cretaceous)* 

 Baiera gracilis (Bean) Bunbury. Oolitic of Yorkshire, England (Jurassic). 



ANAKTOOVUK SERIES (LOWER CRETACEOUS) 



Character and occurrence. — The Anaktoovuk series, named from the 

 river on which it occurs, forms the southern or principal part of the 

 gently rolling Anaktoovuk plateau along the north side of the Endicott 

 range, which it meets at an elevation of about 2,500 feet, as shown in 

 plate 41. Here its inland edge seems to rest unconformably on the 

 Devonian limestone of the Lisburne formation, from whence the series 

 extends northward a distance of about 60 miles, where it unconformably 

 meets and underlies the Nanushuk series. Eastward the Anaktoovuk 

 series is probably soon limited by the front of the Paleozoic range, while 

 to the westward and northward it probably embraces and constitutes 

 the so-called Meade River mountains, and, continuing northwestward, 

 may extend to the Arctic coast. The series consists essentially of heavy- 

 bedded impure, dark-gray, or dirty-greenish, fine or medium grained 

 sandstone. An inspection of their mineral constituents shows that the 

 sediments are obviously derived from the Paleozoic rocks of the range, 

 and especially from the Stuver series. 



Structure. — The strike or trend of the Anaktoovuk series is approxi- 

 mately east and west, with the prevailing dip generally north, so that, 

 broadly considered, the structure is in the main monoclinal. Follow- 

 ing deposition, the beds were gradually uplifted and thrown into gentle 

 anticlinal and synclinal folds, probably in sympathy with the later 

 of the mountain-building forces that were exerted in the range to the 

 south. Two systems of jointing frequently traverse the rocks. Of these, 

 what seems to be the dominant or major system trends northwest 

 and southeast, with dip steeply southward at an angle of 80 degrees, 

 while the secondary or minor traverses the rocks at nearly right angles 

 to the major, with dip 80 degrees southeast, both systems agreeing in 

 general trend with those of the Paleozoics in the range to the south. 



Age. — The series is determined on fossil evidence to be Lower Creta- 

 ceous, constituting the typical Aucella beds of Alaska. Remains were 

 collected at 8 miles north of the foot of the mountains and successively at 

 other points in crossing the series. Of these forms, the principal or most 

 characteristic, as determined by Doctor Stanton, are Aucella crassocollis 



