High-altitude clouds on Neptune have been observed casting shadows on the opaque cloud deck below. There are also high-altitude cloud bands that wrap around the planet at constant latitude. These circumferential bands have widths of 50–150 km and lie about 50–110 km above the cloud deck. These altitudes are in the layer where weather occurs, the troposphere. Weather does not occur in the higher stratosphere or thermosphere. Unlike Uranus, Neptune's composition has a higher volume of ocean, whereas Uranus has a smaller mantle.