13. Sediment Type . Determined by the sand, silt, and clay ratios of 

 the sample based on the F.P. Shephard sediment triangle with modification 

 of coarser material taken from Willman. 



1^. Color . Based on the Geological Society of America Rock-Color 

 Chart. For those samples vhere color was not determined in the field, 

 the sample vas moistened in the laboratory for a color determination. 



15. Odor . A laboratory description. A qualitative description of 

 any noticeable odors. 



16. Size Analysis and Statistical Measures . Sample size fraction 

 values are based on dry weight and given in phy (4) units to the nearest 

 vhole percent. An American Instrument Company sieving machine and U.S. 

 standard sieves vere used for determining sand and larger fractions. 

 The pipette method of analysis was used to determine silt, clay, and 

 colloid fractions. 



The following table is presented for the conversion of phi units to 

 millimeters; 



/P 4 ■ log2 diameter (millimeters J/ 



Phi (4) Millimeters Geological Classification 



<-2 



>k 



Pebble 



-2 to -1 



k.O to 2.0 



Granule 



-1 to k 



2.0 to 0.625 



Sand 



k to 9 



0.0625 to 0.00195 



Silt 



9 to 12 



O.OOI95 to 0.00021* 



Clay 



>12 



< 0.00025 



Colloid 



Qw - (first phi quartile). Is the size read from the distribution 



curve above which 25 percent of the diameters in the distribution 

 are larger and below which 75 percent of the diameters are smaller 

 and is expressed to the nearest hundredth of a phi unit. 



Q^ - (third phi quartile). Is the size read from the distribution 

 curve above which 75 percent of the diameters in the distribution 

 are larger and below which 25 percent of the diameters are smaller 

 and is expressed to the hundredth of a phi unit. 



QDv - (phi quartile deviation). Is that statistical parameter 

 wfiich is a measure of one-half of the spread of the quartiles and 

 is expressed in phi units to the nearest hundredth with the given 

 value computed from the formula: 



180 



