12 MASS. EXPERIMENT STATION BULLETIN 324 



fairly common in the ridges east of the Connecticut Valley- Diorite is of interest 

 because, instead of potash feldspar, it contains lime and soda feldspar; therefore 

 soils weathered from diorite may be poorer in potash than those derived from 

 granite. Phyllite resembles slate in its composition, but does not cleave in thin 

 sheets. It is distinctive in the Bernardston soils and is related in its properties 

 to the slate of Hollis and Dutchess soils. Mica schist represents the dominant 

 rocks underlying the glacial drift from which Berkshire soils have been weathered, 

 and is unlike in color the iron-stained schist of the Brookfield Series. 



Table 5. -Percentages of sand, silt-clay, and potash in some 

 Massachusetts soil series 



Potash 



Soil Series Locality Sand 



Surface Soils 



Becket Windsor 75.4 



Brookfield North Brookfield 80 . 2 



Charlton Paxton 73.7 



Cheshire Amherst 75.2 



Dover Great Bar ringt on 68.9 



Gloucester Hardwick 76. 1 



Holyoke Mt. Tom 70.4 



Lenox Lenox 73.0 



Merrimac Amherst 76.4 



Merrimac Berlin 71.3 



Average of Surface Soils 74.6 13.5 2.07 2.13 



Soils near Ledges 



Diorite Greenwich 74.2 



Mica Schist North Adams 77.2 



Phyllite Clinton 65.9 



Subsoils 



Gloucester Hardwick 74.3 



Brookfield North Brookfield 86.5 



The mica schist soil showed more potash in the sand than in the silt-clay, 

 which may be due to the accumulation of fine mica scales in the sand. The soil 

 from the diorite outcrop was lowest in potash, indicating it to be weathered from 

 the underlying rock. It is possible that the Gloucester soil from Hardwick was 

 influenced by diorite because the glacial movement may have dragged material 

 from the diorite localities onto the Hardwick ridge. A painstaking mineralogical 

 analysis would be necessary to determine the facts. 



The Holyoke soil indicates the mixing effect of glacial action because it con- 

 tains a reasonable amount of potash, although diabase, its dominant rock, con- 

 tains as a rule none. Becket and Brookfield soils have micaceous characteristics 

 and have higher potash in the sands. The two Merrimac soils represent distinctly 

 different formations of water-borne drift. The Amherst soil is an out wash forma- 

 tion, and is not stratified but is irregular in its make-up of clay, sand, and gravel. 

 The Berlin soil represents the typical Merrimac stratification and was underlaid 

 by coarse gravel, which permitted rapid percolation and drainage. The lower 

 potash in the clay may be due to leaching. It may be noted that the percentages 

 in the sands are closely alike in the two samples. 



