*intercalate*

v. t. [ imp. & p. p. Intercalated p. pr. & vb. n. Intercalating ] [ L. intercalatus, p. p. of intercalare to intercalate to intercalate; inter between + calare to call, proclaim. See Calendar. ] [ 1913 Webster ]

1. (Chron.) To insert, as a day or other portion of time, in a calendar. [ 1913 Webster ]

2. To insert among others, as a verse in a stanza; specif. (Geol.), to introduce as a bed or stratum, between the layers of a regular series of rocks. [ 1913 Webster ]

Beds of fresh-water shells . . . are intercalated and interstratified with the shale. Mantell. [ 1913 Webster ]