78 



very large and the coefficient of skewness may differ greatly from 

 unity. If, however, the detritus falls in a region of strong current 

 action the deposits will be well sorted, that is, the coefficient of sort- 

 ing will be small; but the skewness will be much larger than unity 

 because of the plentifulness of rock fragments, which cause the first 

 quartile to be large. These qualities of the coefficient of sorting and 

 skewness may not be unique for deposits of ice-borne origin, but 

 they should aid in the determination of the manner of formation 

 of sediments of unknoAvn derivation. However, as has long been 

 recognized, the presence of faceted subrounded rock fragments is an 

 important diagnostic criterion of an ice-borne origin. 



Table 1. — General description 



1 Writer's sample number. ,. ^ ^. , , , • o -.i a at^^k,- 



2 Station number from Marion expedition. See oceanographic station table m Smith and Mo^Dj , 

 op. m cit. 



i Serial number in writer's general collection. 



