[whittaker] bottom DEPOSITS OF McKAY LAKE 145 



Modern Bottom Deposits 



Field Methods 



In making an examination of the bottom deposits of McKay 

 Lake, a series of traverses 100 feet apart were made east and west, 

 across the lake. The position of each station, fifty to one hundred 

 feet apart, was determined by a line carried out from the shore and 

 in such a small lake this was quite satisfactory. Where necessary 

 stations were occupied at closer intervals. Samples of the bottom 

 were brought to the surface by a miniature orange-peel bucket, com- 

 parable in method of operation to the large dredges. In the soft oozes 

 the bucket often buried itself completely. A small hand dredge was 

 used close to shore for bringing up molluscs and bottom samples. 

 It could not be used in the softer oozes as it would bury itself and fill 

 up completely, rendering it impossible to pull on board. The orange- 

 peel bucket, however, worked very satisfactorily, and very little 

 material washed out as it reached the surface. 



Description of Deposits 



The lake, though small, has several well defined types of bottom 

 deposits with a corresponding difference in fauna in different parts of 

 the lake. As can be seen from the map, the shore for a distance of 

 about four hundred feet on the west side of the lake is composed of 

 walls of sandstone and shaly limestone, either as low cliffs four to six 

 feet high, or sloping back at a more gentle slope. The rock extends 

 outward under the water opposite the rock wall for a short distance, 

 twelve to fifteen feet, but beyond that is covered by recent deposits. 

 These consist of rock fragments and a certain amount of mud and 

 sand. All of these have been derived from the rock wall and above 

 with the exception of possibly some of the sand. The mud has been 

 derived from the soil on top of the cliff. Wave and current action 

 in the lake is negligible and hence to a large extent, except as otherwise 

 noted, the heavier materials such as gravel, sand, rock fragments, etc., 

 are not transported very far beyond their point of origin. In this 

 sediment there are very few water plants and the only organic material 

 consists of dead leaves. These upon decay turn black and as noted 

 later on, the colour seems to be incorporated in the shells of the mol- 

 luscan forms present. 



To the north of the above-mentioned section of the shoreline 

 of McKay Lake, extending quite to the outlet, there is a narrow flat 

 between the elevated land to the west, and the lake. This flat is 



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