MAEIOiSr EXPEDITIOlSr TO DAVIS STRAIT AND BAFFIX BAY 



65 



ence diameter differs someAvhat from the median. Since the median 

 of this sample is 145 microns, the sediment must be a very well- 

 sorted, fine-grained sand. On the other hand, sample 22, is a 

 poorly sorted, fine-grained sand, as So is 7.25 and M is 73 microns. 

 In specimen 2 a range of only 1.87 times the reference diameter 

 accounts for 25 per cent of the sediment, but in sample 22 it requires 



Figure 48 



7.25 times the reference diameter to comprise 25 per cent of the 

 deposit. The latter sediment, therefore, is very poorly sorted; that 

 is, it contains much clay and much coarse sand or gravel. 



Skewness. — If only So and M are given, the relationship of the 

 reference diameter to the median is unknown. The coefficient of 

 skewness, which is a measure of the dissymmetry of the size distri- 



