BULL. GEOL. SOC. AM. 



VOL. 25, 1913, PL. 5 



PHOTO. BY D. D. CAJRNES , 



CANADIAN GEOLOGICAL SURVEY 



Figure 1. — Lower Paleozoic Limestones and Dolomites forming the Summit of Mount 

 Slipper, overlying Tindir Shales 



Figure 2. — Typical Development of Lower Ordoviciax and Cambrian Limestones and 



Dolomites 



Tlie locality is just north of MaCann Hill. The limestones and dolomites on the mountain 

 top in the foreground are overlain, apparently conformably, by Ordovician shales 



CAMBRIAN AND PRE-CAMBRIAN (?) BEDS, YUKON-ALASKA BOUNDARY LINE 



