orbitoidaladj.
/ˌɔːbᵻˈtɔɪdl/, U.S. /ˌɔrbəˈtɔɪd(ə)l/ Geology and Palaeontology.
Of limestone: containing shells of foraminiferans, esp. orbitoids. Also: relating to, characteristic of, or designating such foraminiferans.
ΘΚΠ
the world > the earth > structure of the earth > structural features > formations by contents > [adjective] > containing organic remains > containing shells
shelly1555
shell1587
conchylaceous1799
conchitic1811
conchiferous1830
orbitoidal1848
1848 C. Lyell in Q. Jrnl. Geol. Soc. 4 i. 13 The nummulitic or orbitoidal limestone of Alabama.
1876 D. Page Adv. Text-bk. Geol. (ed. 6) xix. 363 The nummulitic and orbitoidal limestones, mainly composed of coin-shaped and globular foraminiferal shields, are undoubtedly the most important of tertiary strata.
1929 Proc. National Acad. Sci. U.S.A. 15 295 The orbitoidal foraminifera discussed in this paper are of interest.
1961 J. Stubblefield Davies's Introd. Palaeontol. (ed. 3) x. 239 The Oligocene Lepidocyclina limestones (commonly known as orbitoidal) have a similar distribution.
2002 Micropaleontology 48 79 It [sc. a new foraminiferan genus] is characterized by the presence of the trochospiral early orbitoidal adult chambers and by the lack of vertical canals in the large umbilical plug.
This entry has been updated (OED Third Edition, September 2004; most recently modified version published online March 2022).
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adj.1848