TABLE OF FORMATIONS 

 Dominwntly Sedimentary Rooks 



Era 







Northern section 



Intermediate section 



Southern section | 







Formation 



Thickness 

 in feet 



Lithological characters 



Formation 



Thickness 

 in feet 



Lithological characters 



Formation 



Thickness 

 in feet 



Lithological characters 



Remarks 



Quaternary 



Recent and Pleistocene 



Superficial 

 deposits 





Gravels, sands, clays, peat, 

 soil and ground-ice 



Superficial 

 deposits 





Gravels, sands, clays, peat, 

 soil and ground-ice 



Superficial 

 deposits 





Gravels, sands, clays, peat, 

 soil and ground-ice 





Mesozoic 



Probably mainly Lower Cre- 

 taceous 



Orange group 



4,000 

 2,000 



Conglomerates, sandstones, 

 shales, slates, phyllites, and 

 quartzites, as well as occa- 

 sional limestone beds in 

 lower portion of group 















Probably corresponds to the Laberge 

 series of Yukon. Contains inver- 

 tebrate remains 





Carboniferous 



Permian 



Pennsylvanian 



Mississippian 





800 + 



Reddish conglomerate con- 

 taining considerable iron in 

 places, possiblv consoli- 

 dated boulder clay 



Reddish conglomerate may represent 

 former Permo-Carboniferous gla- 

 cial period 





Nation River 

 formation 



4,000 + 



Conglomerates, sandstones, 

 and shales 









Racquet 

 group 



1,500 + 



Dominantly white to grayish lime- 

 stones, containing considerable 

 chert in places, and also some 

 shales and occasional cherty con 

 gloraeiate beds 



fnXr"^ 

 Calico Bluflf 

 formation 



800 + 



Interbedded limestones and 

 shales, dominantly cal- 

 careous 



Nation River formation contains 

 abundance of plant remains 







600 + 



Interbedded black, gray, and 

 red shales and cherts, in- 

 cluding some calcareous 

 shales 







Paleozoic 



Devonian 



Includes 



Salmontrout 



limestone 



300 + 



Light to dark gray crystalline 

 limestone 





300 + 



Interbedded black, gray, and 

 red shales and cherts 



abundance of invertebrate remains 











4,000 + 



Limestones and dolomites, 

 dominantly very siliceous 







Silurian 





4,000 + 



Limestones and dolomites, 

 dominantly very siliceous 



Unmetamorphosed 



Devonian, Silurian, Ordovician, and 

 Upper and Middle Cambrian beds 

 are fossiliferous. Several hundred 

 feet of unfossiliferoua limestones 

 and dolomites, considered to be 

 probably Lower Cambrian, under- 

 lie the beds which contain Middle 

 Cambrian fossils 





Ordovician 





Cambrian 





3,000 + 



Limestones and dolomites, 

 dominantly very siliceous 



Unconformity 



Tindir 

 group 



Dolomites, quartzites, and 

 shales, with some included 

 greenstones 



Tindir 

 group 



tes, quartzites, and 

 shales, with some included 

 greenstones 



Unfossiliferous 



Indurated, but only slightly 

 morphosed 



Metamorphic rocks 



Pre- 

 Cambrian (?) 



Yukon 

 group 



Schistose ampliibolites,quartz- 

 ite schists, and mica schists; | 

 also includes occasional ; 



Highly metamorphosed 



It is from the members of this group 

 that the placer gold in the Klondike 

 and other important mining dis- 

 tricts in Yukon and Alaska has 

 been derived 



Igneous rocks 



Mesozoic 



Range from 

 Mesozoic 



Granites, granodiorites, and 

 syenites 



Diabases, diorites, andesites 

 and other basic intrusives 



Diabases, diorites, andesites 

 and other basic intrusives 



Occur dominantly associated with pre- 

 Canibrian (?) forujations. Similar 

 appearing rocks also occur as occa- 

 sional dikes and small intrusive 

 masses cutting Mesozoic sediments 



