450 W. A. Johnston — Delta of Fraser River. 



Akt. XXXIV. — The Age of the Recent Delta of Fraser 

 River, British Columbia, Canada;^ by W. A. Johnston. 



One of the problems studied in connection with an 

 investigation of the characteristics of Fraser river, Brit- 

 ish Columbia, by the Geological Survey, Canada, in co- 

 operation with the Department of Public Works, in 1919 

 and 1920, was the question of the age or time which has 

 elapsed during the period of formation of the Recent 

 or modern delta of the Fraser. This is of interest not 

 only in itself, but because there has been much dispute 

 in recent years as to whether uplift has continued into 

 Eecent time ; in regions such as the Fraser Delta region 

 where post-glacial uplift is known to have taken place. 



The Recent, or modern, delta of Fraser river, British 

 Columbia, is for the most part sharply delimited from the 

 raised delta and marine deposits formed during the period 

 of uplift of the land at the close of the Pleistocene. The 

 surface of the Recent delta is all, except in a few places 

 where the surface of peat bogs is a few feet above the 

 general level, below the level of high tide ; and the delta 

 land high enough to be reclaimed is diked to exclude the 

 flood-tidal and freshet waters. The head of the Recent 

 delta, as defined by the point where the first distributary 

 is given oif, is at the city of New Westminster, 19 miles 

 upstream or east from the seaward front of the delta in 

 the Strait of Georgia. At New Westminster the river 

 is confined between drift ridges or upland areas, which 

 rise 200 to 300 feet above the river; and the river has 

 occupied the valley between these ridges throughout the 

 time of formation of the Recent delta. The upland 

 area south of the river marks the inner edge of the delta, 

 and extends from a point on the river Sj^ miles below 

 New Westminster nearly straight south to Boundary 

 Bay. The delta is bounded on the north by the highland 

 area extending from New Westminster nearly west to 

 Point Grey. In its seaward part on the south side it is 

 interrupted by the highland area of Point Roberts, an 

 island-like drift hill which has been joined to the mainland 

 by the construction of the delta. Above New Westmin- 

 ster there is a large area extending from the south side 



^ Published by permission of the Director of the Geological Survey^ 

 Canada. 



