(2 RECONNAISSANCE IN NORTHERN ALASKA IN 1901. 



In tin' Cape Lisburne region, as noted, the bell has a known width of nearly 7.". 

 miles and the rocks terminate in abrupt sea cliffs. The thickness of the section here 

 is not known. but from what has been learned of the attitude of the rocks, it is 

 judged to be considerable, since nowhere do older rocks appear to be exposed beneath 



these Paleozoics; from which it seems safe to infer that the latter probably extend 

 far seaward as a submarine feature: and as this part of the ocean is known in the 

 main to lie shallow, it seems not unlikely that the same formations may extend across 

 its floor and appear on the Siberian coast. It may lie noted, however, that Doctor 

 Dall, who visited this coast, reports that the rocks on portions of it are essentially 

 crystalline or igneous. Some lignite occurs on Wrangell Island, but we do not 

 know that Paleozoic or other formations occur there. 



MESOZOIC ROCKS. 



CORWIN SERIES (.TURA-CRETACEOUS). 



Character ami occurrence. — The name Corwin is proposed for a series of sedi- 

 mentary rocks which are younger than the Fickett series and older than the Anak- 

 tuvuk series (next to be described). The name is taken from Corwin Bluff, in the 

 Cape Lisburne region (see PI. V), where the well-known coal mines of this name are 

 located, and where rocks typical of the series are well exposed. 



The rocks in the main have a strong lithologic resemblance to the Anaktuvuk 

 series, and seem to be closely related to it in geographic and stratigraphic position, 

 but as they are not known to occur in the interior along the route follow, d by 

 this traverse, they will not be found represented on the geologic map nor in the 

 geologic section. However, sufficient has been seen of the rocks along the coast from 

 Wainwright Inlet to near Cape Lisburne to lead to the inference that they probably 

 form a part of the trans-Alaskan Rock} 7 Mountain system; and on topographic, 

 geographic, and lithologic grounds, as shown in what follows, it has been con- 

 cluded that they are intermediate between the Fickett aud Anaktuvuk series, a view 

 which is also supported by paleontologic evidence. The series contains the Wain- 

 wright, Cape Beaufort, Thetis, and Corwin coals, most of which are of good grade. 

 The inland extension of the series is also further suggested by the occurrence of coal 

 on the Colville, reported by Howard and by Reed (see p. 31). 



As observed along the coast, the Corwin series seems to extend from near Wain- 

 wright Inlet, latitude 70° 37', longitude 159° 45', southwestward a distance of 180 

 miles or more, nearly to Cape Lisburne (see PL V). Beyond this point, farther 

 inland, it seems to give way with marked unconformity to the Paleozoic rocks 

 forming the core of the mountains terminating in the sea cliffs at Cape Lisburne and 

 the coast south of that point (fig 1, p. 40). 



