SEDIMENTS IN THE DELTA OF ERASER RIVER 123 



show no definite lamination. The stratification of the sandy be.ds 

 is in places rendered visible by thin partings of silt and clay. The 

 stratification of the beds in the intertidal zone is very marked, the 

 characteristic feature being a very thin tidal lamination. Bottom 

 sample No. i, shown in Figure i, illustrates the character of the 

 stratification of part of the beds in the intertidal zone. The light- 

 colored parts are silty in character and the dark parts are sandy. 

 The seasonal character of these beds is indicated in places by 

 layers of vegetable matter, and in other places by the different 

 character of the laminae formed during the freshet stage of the 

 river, from those formed during the low-water stage. During 

 the freshet the water holds in suspension considerable quantities of 

 silt, and during the low-water stage it is nearly clear. Hence the 

 laminae formed during the freshet are largely silt, and those formed 

 during the low-water stage are largely fine sand. The tidal laminae 

 average possibly 15 to 20 to the inch. The seasonal layers average 

 about 5 or 6 to the foot. But as contemporaneous erosion and 

 deposition are constantly going on, any one section gives a very 

 incomplete record of either the tidal laminae or seasonal layers. 



The stratification of the alluvial flood-plain deposits differs 

 from that of the tidal flood-plain deposits because of the fact that 

 during the freshet the surface of the part of the river above New 

 Westminster is raised above the normal level and falls very little 

 with the tides. Hence, during the freshet, a single layer of silt, 

 which may be as much as | inch in thickness, is deposited on the 

 alluvial flood plain. Neither the tidal nor the alluvial flood-plain 

 laminae show any marked gradation upward from coarse to fine 

 particles in the individual laminae. 



The character of the stratification in the fore-set beds of the 

 Fraser Delta is indicated approximately in samples Nos. 6, 7, and 8 

 shown in Figure i. The beds are composed of a mixture of fine 

 sand (o.i to 0.05 mm.), silt (0.05 to 0.005 mm.), and clay (less 

 than 0.005 mm.). They are, for the most part, thinly laminated, 

 in a somewhat similar manner to the tidal flood-plain deposits. 

 In places the lamination is even, in other places it is markedly 

 irregular, and cross-bedding as well as inclined bedding occurs. 

 The lamination is tidal in character, but is the result of the com- 



