Lake Louise, Alberta, Canada. 381 



carried in suspension only slightly increasing its dens- 

 ity — the river water tends to diffuse through the lake 

 water. At times it is lighter than the lake water and 

 flows out on the surface over the subaqueous part of the 

 delta, but only for a distance of 200 or 300 yards. At 

 times also wind-induced currents carry the turbid river 

 water out into the lake farther than usual or shift it from 

 one side of the delta to the other. There is apparenly 

 no tendency, so far as could be observed, for the river 

 currents to follow the bottom of the lake and the diffusion 

 through the lake of the silt in suspension and the steep 

 underwater face of the delta seem to show that no 

 appreciable currents follow the lake bottom. 



The material forming the subaqueous part of the delta 

 is silt and very fine sand. The very fine sand is probably 

 moved along the bottom by current action and comes to 

 rest along with the part of the silt which is too coarse to 

 remain in suspension, when the current is checked. The 

 underwater face of the delta is remarkably steep in its 

 upper part, in spite of the fineness of the material. The 

 soundings indicate that the slope is in places as much as 

 8 degrees. It is probable, therefore, that foreset bedding 

 is well developed in the delta and that the material is 

 marked by very fine laminations due to short, interrupted 

 periods of sedimentation. 



Figure 1 shows two core samples from the bottom of 

 the lake, and, by way of comparison, one sample from the 

 Champlain glacial clays of the Ottawa valley. The 

 material from the bottom of the lake is mostly very fine- 

 grained and of a uniform grayish white color. It is de- 

 rived mostly from erosion of Cambrian quartzites and 

 is therefore highly siliceous in character. Because of the 

 unweathered character and uniform color of the samples 

 the character of the stratification cannot be well shown 

 by the photograph. The stratification is also somewhat 

 distorted by the action of the bottom sampler and the 

 samples are somewhat compressed but probably not much 

 more than the lower compacted beds of the silt. These 

 were found to be quite firm at a shallow depth. The 

 bottom sampler, weighing 55 pounds, penetrated to a 

 depth of only 3 feet or 4 feet when allowed to fall freely 

 from the surface. 



