ICE-CLIFFS ON WHITE RIVER, YUKON TERRITORY 117 



of the confluence of the White and Katrina, scores of tliem being vis- 

 ible from the summit of a small table-topped mountain immediately 

 west of tlie mouth of the latter stream. There is no reliable map of 

 the White and its tributaries in existence, since nearl}'' all of them 

 show Ladue Creek as about equal, if not superior, to the Katrina in 

 size, whereas it discharges less than one-tenth as much water as the 

 latter, which almost equals the main stream in size. The Nisling 

 River of the maps I was unable to find unless it is represented by a 

 comparative!}' small creek which does occur in the vicinity indicated. 



There is considerable evidence of recent volcanic activity in the 

 valley of White River, and this evidence is much more pronounced 

 in the region between the White and Yukon. It is in this section 

 that we must look for the mountain or caldera responsible for the 

 immense deposit of volcanic pumiceous ash Avhich forms so notice- 

 able a feature of the banks of the Yukon from Caribou crossing to 

 Dawson, a distance of 520 miles by the course of the stream. There 

 is not a trace of it to be seen along the banks of the White except 

 near the mouth, while it is very noticeable along the banks of some 

 of the creeks between the latter and the Yukon. This would })re- 

 clude the possibility of this deposit being caused by an outburst from 

 Mt Wrangell, as suggested by Dawson,* as an outburst from an}'- 

 mountain in the vicinity of Wrangell would undoubtedly de})Osit 

 even a greater layer of the ash on tlie White than it would on the 

 Yukon. 



Another theory regarding this deposit, t viz., that it is not of recent 

 date and that deposition took place in water while the upper Yukon 

 was yet a great inland lake and before tlie present river channel had 

 been cut, is also untenal^le, as the ash in many places may be found 

 overlying old drift-piles of perfectly sound wood, notably at the mouth 

 of Stewart River and again above the mouth of tlie Pelly. It there- 

 fore still remains for some energetic memlier of the next Dominion 

 Geological Survey party that traverses this region to locate the caldera 

 from which such an extensive and remarkalile deposit has been 

 ejected. The solution of the question is certainly worthy of an effort, 



* Ili-piHt ■111 ;iii .■.\|iloi;itinii ,,( tlir ViikiMi ilisli'ict, N. W. T., 1887, Georgo M. Ihiwsiiii, ]<. 45. 

 B. I)iHVSon 1510S., ISNS. 

 t.M.'i.HkHiinil iIh' KloridiU.-, Anjifld ll(il|iiipi. 1 1. Appl.'ldii A <<■., iK'.ili. 



