LOWER CRETACEOUS. 



633 



Wright has also found a conglomerate sandstone and shale series on Kupreanof Island, 

 a few miles south of Admiralty Island, which carries plant remains assigned to the Upper 

 Cretaceous. Knowlton reports on these fossils : 



"These plants indicate beyond question that the age is Cretaceous, and I would place them 

 in the lower part of the Upper Cretaceous, or approximately of Cenomanian age." 



It appears that these Upper Cretaceous beds are discordant to Aucella-bearing terranes 

 of the adjacent region, and that they are conformably succeeded by the Kenai (Eocene) rocks, 

 with which they are lithologicaUy identical. 



Later information by Wright ^^^ is as follows : 



[Part of] stratigraphic column in southeastern AlasJca. 



O-P 4. LOWEK. YUKON AND KXTSKOKWIM BASINS, ALASKA. 



The so-called Cretaceous of the Kuskokwim basin, represented as Lower Creta- 

 ceous on the map, comprises both sedimentary and volcanic rocks which constitute 

 three different series, according to Spurr, and which may be older than Cretaceous, 

 according to Brooks. ^"^^ 



Spurr subdivided the Mesozoic rocks of the Kuskokwim Valley into three series, all Creta- 

 ceous, of which the Holiknuk and Kolmakof series are supposed to be synchronous, while the 

 stratigraphic relation of the third — the Oklune series, which is Jura-Cretaceous — to the others 

 is unknown. The Holiknuk series is made up of alternating sandstones, argOlaceous and 

 siliceous limestone containing fragmentary Cretaceous fossils, and shale and arkose, all thrown 

 up in broad open folds. An unconformity determined the line of demarcation between these 

 beds and the underlying Tachatna series (Devonian). 



A succession of volcanic rocks of various types occurs to the southwest, and these, together 

 with some intercalated tuflfs, shales, impure limestones, and arkoses, form Spurr's -Kolmakof 

 series, supposed to be synchronous with the Holiknuk beds. A group of sediments, including 

 shales, impure limestones, with some arkoses, received the name "Oklune series," from the 

 mountains where they are typically exposed. These beds are referred to the Jura-Cretaceous 

 on the evidence of some fragmentary fossils. As far as the facts presented can be interpreted, 

 all three of these series may belong to the same horizon. All three exhibit about the same 

 amount of deformation and are intruded by igneous rocks of various kinds. If they are not of 



