64 



MARION ' EXPEDITION TO DAVIS STRAIT AND BAFFIN BAY 



Consequently the coefficient of sorting indicates whether or not 

 particles of about the size of the median are plentiful. For example, 

 in sample 2, /So is 1.87, which means that 50 per cent of the weight 

 of the sample is composed of particles that differ in diameter less 

 than 1.87 units from a certain reference diameter; that is, 25 per 

 cent of the sample is composed of particles larger than 1.87 times 



FiGUUE 41 



the size of this reference diameter, 25 per cent of particles smaller 

 than 1/1.87 times the reference diameter ; and 50 per cent within the 

 diameter range of 1.87 units on either side of the reference diameter. 

 If the histogram of the size distribution were symmetrical, the 

 reference diameter would be the same as the median, but since 

 the size distribution of most sediments is uns3'mmetrical, the refer- 



