NOTE ON THE ACTION OF FROST ON SOIL ^IJ 



had shrunk by melting to such an extent that the total height of 

 the eight layers was less than three inches, and the separate 

 layers could be distinguished only in a few places. 



The following conditions prevailed and seem to have con- 

 trolled the formation of these many-storied frost-forms: (i) 

 ground which was not frozen and which was readily permeable 

 to moisture ; (2) freezing temperature at night ; (3) mild thaw- 

 ing in the daytime; and (4) considerable moisture in the soil. 



MiLNOR Roberts. 

 University of Washington, Seattle, 

 February 20, 1903. 



