NOME SMITHSONIAN EXPEDITIONS, IQIO-IQII 4I 
system in this portion of the Rocky Mountains. This discovery 
led to the study of the pre-Cambrian rocks of the Bow River Valley. 
These were found to form a series of sandstones and shales some 
4000 feet in thickness, that appear to have been deposited in fresh- 
water lakes prior to the incursion of the marine waters in which the 
great bed of conglomerate and the Cambrian rocks above were 
deposited. 
Completing the reconnaissance survey of the Bow River area, 
Fic. 45.Northern end of fossil quarry in Middle Cambrian Burgess shale 
about 700 feet above Burgess Pass trail on ridge between Mount Wapta and 
Mount Field, about 8 miles from Field, British Columbia. Photograph by 
Walcott. 
camp was moved to the Yoho River Canyon. In this canyon, one 
of the most picturesque and instructive areas in the great Yoho 
National Park of Canada, a study was made of the north side of 
the President Range and numerous pictures were taken in that vi- 
cinity, as well as from Burgess Pass, north of Field. 
A most interesting discovery of unique Cambrian fossils was made 
near Burgess Pass and a number of specimens collected before the 
snow drove the party back to Field. Three days were then spent on 
Mount Stephen, at the famous trilobite beds, before breaking up 
camp on September 8, 1909. 
