The part of the Southern Foothill section, Arctic foothills province, that lies beteween the Etivluk and Kiligwa Rivers was investigated by Navy Oil Unit party 6 during the 1950 field season, A belt about 16 miles wide and 60 miles long (approximately 800 square miles) was mapped in considerable detail (see index map, pl. 1). The mapped area is in the west-central part of the Arctic Foothills province, wholly within the boundaries of Naval Petroleum Reserve No. 4. Major drainage consists of the middle reaches of the Etivluk, Ipnavik, Kuna, and Kiligwa Rivers.
Principal objectives of the party, using previous geologic studies in. the Okpikruak-Kiruktagiak Rivers area 1/ ao an initial working base, were stratigraphic and structural studies of the outcrops in the interstream areas. In view of the former interest in possible Lisburne limestone plays, the Lisburne Ridge west of the Etivluk River and the northward nosing of the Triassic complex between the Ipnavik and Kuna Rivers were designated as areas for particular emphasis.
The party included six men: two geologists; two field assistants, a cook, and a weasel mechanic. Three weasels were available for transportation; two of which were maintained in operating condition for daily field use.
As many exposures as were pertinent or accessible were examined. Vertical photographs were used for plotting data and for areal control; relative vertical control was established with altimeters, The effective working radius from base camp as increased from 8 miles to 20 miles by making frequent 2- or 3-day spike trips.
