loo BEACH GRASS 



lie, and often grown up to bushes and trees. 

 Generally dry in summer, they contain small 

 ponds in the spring. A good example is not far 

 from my house at Ipswich. They are believed 

 to have been formed at the end of the last glacial 

 period by the slow melting of detached masses 

 of ice buried in the moraine. 



I had always some difficulty in picturing in 

 my mind the formation of these familiar features 

 in glacial landscapes until I came across a descrip- 

 tion by John Muir of a kettle-hole in process of 

 formation in Alaska. "I found a pit," he says, 

 "eight or ten feet deep with raw shifting sides 

 countersunk abruptly in the rough moraine mate- 

 rial and at the bottom, on sliding down by the 

 aid of a lithe spruce tree that was being under- 

 mined, I discovered, after digging down a foot 

 or two, that the bottom was resting on a block 

 of solid blue ice which had been buried in the 

 moraine perhaps a century or more, judging by 

 the age of the tree that had grown above it. 

 Probably more than another century will be re- 

 quired to complete the formation of this kettle 

 by the slow melting of the buried ice-block. The 



