Kettle lakes are circular depressions that are usually formed by the burial and subsequent melting of a block of ice.
(Kettle lakes; are; circular depressions that are usually formed by the burial and subsequent melting of a block of ice) (circular depressions; are formed; by the burial and subsequent melting of a block of ice; T:usually)
Kettle lakes circular depressions
are are formed
circular depressions that are usually formed by the burial and subsequent melting of a block of ice
by the burial and subsequent melting of a block of ice T:usually