surface layer

This class is distinct from a geometric surface, which is two-dimensional. The idea of "uppermost" may be problematic. Further, the definition of layer (the superclass of surface in rev 133) references surface. This may be another issue. Perhaps this can be made into an inferred class using 'bounding layer of' some material entity, note that 'bounding layer' implies containment, which may not be valid here. A layer of some material entity which is adjacent to one or more of its external boundaries and directly interacts with its immediate surroundings.

http://purl.obolibrary.org/obo/ENVO_00010504

This class is distinct from a geometric surface, which is two-dimensional. The idea of "uppermost" may be problematic. Further, the definition of layer (the superclass of surface in rev 133) references surface. This may be another issue. Perhaps this can be made into an inferred class using 'bounding layer of' some material entity, note that 'bounding layer' implies containment, which may not be valid here.

https://en.wikipedia.org/wiki/Surface

SWEETRealm:Surface

EcoLexicon:surface

A layer of some material entity which is adjacent to one or more of its external boundaries and directly interacts with its immediate surroundings.

surface layer

ENVO:00010504

surface layer

http://purl.obolibrary.org/obo/ENVO_01000281