A PECULIAR FORMATION OF SHORE ICE 137 



seems the same as the outer parts. As the balls grew in size, it 

 is evident that they rolled on the solid beach, gathering up a layer 

 equal to the thickness of the snow on the beach, and including a 

 thin layer of the sand and small gravel in the bottom of the layer. 

 The scarcity of the phenomenon seems amply accounted for by 

 the peculiar conditions necessary for its production. There must 

 be wide, flat beach such that the surge of the waves can carry them 

 forward and back for a considerable distance; the water must be 

 reduced to the freezing-point without the formation of an ice-foot 

 which would hold the waves off the beach; and there must be a 

 mass of soft, damp snow ready for the action of the waves. 



