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SOMERS: MICROSCOPIC EXAMINATION OF CLAYS 



TABLE I 

 The Composition of Clays 



° The minerals listed here represent the identifiable grains, but some of them 

 contain a variable quantity of exceedingly small grains not identifiable, and which 

 are indicated in the column headed Colloid matter. Aside from this, most of the 

 clays undoubtedly contain colloidal particles so small as not to be visible with the 

 ordinary microscope. 



'' S, scarce; C, common; M, moderate amounts; A, abundant; V A, very abundant. 



