a. and sb. [f. FUC-US + -OID. Cf. F. fucoïde.]
A. adj. a. Resembling or belonging to seaweeds, esp. those of the group Fucaceæ. b. Characterized by or containing impressions of such seaweeds or markings similar to them.
1839. Roberts, Dict. Geol., Fucoïd.… A term applied to several fossil plants. There is a fucoïd shale, so called from the abundance of fuci it contains.
1854. Murchison, Siluria, vi. 136. In the cliffs at Ludlow, the chief rocks are surmounted by what I termed the fucoid bed. This is a greenish-grey argillaceous sandstone, almost entirely made up of a multitude of small, wavy, rounded, stem-like forms, which resemble entangled sea-weeds.
1871. Lyell, Student’s Elem. Geol., xxvii. 473. These sandstones have been called in Sweden ‘fucoid sandstones.’
B. sb. a. A seaweed of the group Fucaceæ.
b. A fossil marine plant resembling these.
1848. Craig, Fucoid, a fossil plant belonging to the order Fucaceæ.
1857. H. Miller, Test. Rocks, i. 17. The fucoids, or kelp-weeds, appear to have had also their representatives in such plants as Fucoides gracilis of the Lower Silurians of the Malverns.
1859. D. Page, Handbk. Geol. Terms, s.v. Fucoids, or fucus-like impressions, occur in strata of every epoch, from the Lower Silurians to the Upper Tertiaries.
1860. Hartwig, Sea & Wond., iii. 30. The variety of interesting objects which the reflux of the tide leaves behind it on the beach—the elegantly formed shell, the feathery sertularia, the delicate fucoid, and so many other strange or beautiful marine productions, that may well challenge the attention of the most listless lounger.
1860. All Year Round, No. 50. 562. Little fucoids, progenitors of the kelp-weeds.
1872. Nicholson, Palæont., 477. The Lower Cambrian Rocks have yielded many so-called ‘fucoids’; but these are almost invariably to be referred to the tracks and burrows of marine worms.
