interbed
1 of 2verb
in·ter·bed ˌin-tər-ˈbed 
interbedded; interbedding
intransitive verb
: to lie or settle in sedimentary layers between other existing layers
… consists of … sandstones of variable thickness that interbed with grey and greenish shales.
D. J. W. Piper
D. J. W. Piper interbedded adjective
The factory crushed shale extracted from the site, discarded the interbedded limestone, and baked the clay into bricks. Patrick L. Hamilton
Patrick L. Hamilton interbed
2 of 2noun
plural interbeds
: a typically thin layer of one kind of sedimentary material located between layers of another kind
… it ranges from boulder gravel to pebble gravel, with local interbeds of sand … R. B. Morrison
R. B. Morrison
Word History
First Known Use
Verb
1858, in the meaning defined above
Noun
1942, in the meaning defined above