Far on the horizon they could make out great billowy masses of white cloud.

Usually the clouds are of the cumulus variety and roll leisurely by in billowy masses.

Just then another steamer entered the harbour, an enormous leviathan from whose funnels smoke poured in billowy masses.

It blew out of the canyon-mouth like a gust from a chimney, rolling over and over in billowy masses.

The horses at once ran away and hid themselves in the clouds, which hung down from the mountains in soft billowy masses.