Hill RECONNAISSANCE IX NORTHERN ALASKA IX 1901. 



In th* Fickett series. — Toward the northern edge of the Fickett series, east of 

 John River, in the Fork Peak region, where the country rock consists of heavy- 

 bedded gray and pinkish quartzite and slate, there i- ; \ belt about 2 mile- wide which 



is stained bright reddish in-own. purple, and some other eolors. As shown on the 

 map. this belt also trends northeastward a distanee of apparently about L"> miles to 

 a point where the Fickett series gives way to the Lisburne formation. It seems also 

 to extend southwestward beyond John River, but in that direction it is apparently 

 not so conspicuous. 



Here again the stain, which is surficial, is due to iron pyrites acted on by the 

 process of weathering. A fresh fracture surface in hand specimen shows the zone of 

 stain or weathering to be nearly always definitely marked, but in its penetration of 

 the rock it may vary in different cases from a mere film to a zone nearly one-fourth 

 inch in thickness. As the rock is known to contain iron pyrites very finely dissem- 

 inated, and all of the five stained specimens tested by the chemical laboratory were 

 found to contain ferric oxide (Fe 2 3 ), with some sulphuric oxide (S0 3 ) present in four 

 cases, the stain seems undoubtedly to be iron oxide derived from the pyrites by 

 process of weathering. The brilliant peacock or bornite color, which by the inexpe- 

 rienced prospector would readily be mistaken for indications of copper, is iridescent 

 hematite. The specimen in which no sulphuric oxide occurs was found to contain also 

 siderite (FeC0 3 ). 



Whether these zones of mineralization may prove to be of economic value can 

 not be affirmed at present, as the rapid progress of the party through the country 

 did not permit opportunity for examination. It may be noted, however, that both 

 zones are closely related to formational boundaries, the southern being near the 

 unconformable and probably deformational contact of the Totsen series with the 

 Skajit formation, while the northern lies along the fault contact of the Fickett series 

 with the Stuver series and Lisburne formation; and both zones trend in a general 

 waj T parallel with the dominant jointing or major structure of the mountain range. 

 The localities at which placer gold claims have been staked by prospectors, and gold 

 colors panned by the writer on John River, lie within the southern zone. 



COAL. 

 GENERAL STATEMENT. 



Coal in one form or another, and varying in age from Tertiary to possibly Car- 

 boniferous, is more or less widely distributed in northern Alaska. It occurs in the 

 Koyukuk drainage on the south side of the mountains, in the plateau on the Anak- 

 tuvuk, in the coastal plain on the Colville, and on the northwestern coast, in what is 

 commonly known as the Cape Lisburne region, at Wainwright Inlet, Cape Beaufort, 

 and several points between Cape Beaufort and Cape Lisburne (PI. V). 



