Geological Survey Party 1 returned to Umiat from Wolf Creek on August 5. Plans for the field season of 1947 called for geologic reconnaissance along part of the Ipnavik River and along the Colville River between the Ipnavik and Kurupa Rivers, to be completed before the end of the season. Since not much time remained and the traverse was long--about 70 airline miles--it was decided that the work would progress more rapidly if two parts of the traverse were worked at the same time. Accordingly, Robert F. Thurrell, Jr., and James H. Zumberge, geologists, were transported by plane from Umiat to the confluence of the Ipnavik and the Colville Rivers on August 8. From there they traversed down the Colville to the Kurupa River 1/.
The other two members of Party 1, Karl Stefansson, geologist, and Elder W. Lebert, cook, remained in Umiat until August 14 when a small plane was finally available to transport them to a camp on the Ipnavik River, about 30 airline miles southwest of the junction of the Ipnavik and the Colville Rivers. The party reached the Colville River on September 2, and arrived at Umiat on September 6.
Preliminary report on the stratigraphy and structure of the area of the Ipnavik River, Alaska