"Layer clouds" refers to clouds that form in flat, horizontal sheets or layers across the sky. They often appear like a blanket covering a large area and can be seen at different altitudes. Full definition
Instead, clouds are treated in one subsection of chapter 8 and boundary layer clouds in one paragraph. (climate-skeptic.com)
The marine layer clouds of a June Gloom day usually are at their maximum at dawn, when the surface air is at a minimum temperature and the temperature difference in the inversion layer is at its maximum. (en.wikipedia.org)
For example, Chagnon et al. (2004) find a large increase in boundary layer clouds in the Amazon in areas of partial deforestation (also, e.g., Durieux et al., 2003; Ek and Holtslag, 2004). (ipcc.ch)