Illustration of a cirrocumulus cloud, a large, white patch or tuft without a gray shadow. Composed of supercooled liquid droplets (if they freeze, becomes cirrostratus - cirrocumuli are short lived) Each cloudlet appears no larger than a finger held at arms length. It occurs in patches or sheets, organized in rows like other cumulus, but since they are so small, cirrocumulus patches take on a finer appearance, sometimes referred to colloquially as "herringbone" or "mackerel"
Illustration of a nimbostratus cloud, a rain cloud characterized by a formless layer that is almost uniformly dark gray, of medium altitude, usually developing above 6500 ft (2000 m). Nimbo is from the Latin word "nimbus" meaning rain. They may block a great amount of sunlight as a result of their characteristic dense structure