We turned instantly in that direction.

The whole pack of ice, filling the arm for near a half-mile, was in motion, grating and grinding together.

From where we stood, the noise more resembled heavy, near thunder than anything else I can compare it with.
"It's the tide bursting round from the north-east side!" exclaimed Kit.
"Took it a little longer to come in among the islands on the north side," said Raed, gazing intently at the fearful spectacle.
The noise nearly deafened us.

The whole vast mass of ice--millions of tons--was heaving and sliding, cake over cake.

It had lain piled fifteen or twenty feet above the water; but the tide surging under it and through it caused it to mix and churn together.