Geol. [f. CORN sb.1 + STONE.] A name, originally local, for an earthy concretionary limestone, mottled red and green, forming a subordinate bed in the Old Red Sandstone formation in varions parts of Britain.
‘They are said to derive their name from the fertile corn-soil that overlies them in Hereford, as compared with the tenacious clays which cover the marls and sandstones’ (Page, Handbk. Geol. Terms.)
1822. Conybeare & Phillips, Outl. Geol. Eng. & Wales, 362. A rock of a pseudo-brecciated appearance, known by the name of Corn-stone.
1877. A. H. Green, Phys. Geol., II. § 6. 73. Passages sometimes occur from Calcareous Sandstones into Limestone, and the intermediate forms are called locally Cornstones.
attrib. 1842. H. Miller, O. R. Sandst., viii. (ed. 2), 176. The Cornstone formation is more extensively developed in Forfarshire.
1881. Whitehead, Hops, 22. The Cornstone division of the old Red Sandstone formation.
